Tutorials/Defeating the ender dragon

The ender dragon is one of the two bosses in Minecraft, along with the wither. It lives in the End, and is usually considered the final boss of the game, even though it was added first and the achievements related to the wither are unlocked after defeating the dragon.

The dragon is highly anticipated to fight because its defeat will give the player access to the End's outer islands easily, as it generates an end gateway portal when defeated. It will also activate the exit portal and allow the player to return to the Overworld.

Ender dragon boss fight checklist
Defeating the dragon requires a lot of preparation, but not everyone has the same skills. So depending on how skilled the player are, different preparations may be needed. The following is a suggested collection of equipment they might need:


 * A diamond sword enchanted with Sharpness V, Looting III, and Fire Aspect II (Knockback is effective against the endermen, but not the dragon)
 * A bow enchanted with Unbreaking III, Power V, and Infinity (Flame and Punch are ineffective)
 * One arrow (or without Infinity, several stacks)
 * A full set of diamond armor enchanted with Protection IV, Unbreaking III, and Thorns II or III (boots enchanted with Feather Falling IV)
 * A diamond pickaxe enchanted with Silk Touch and Efficiency IV or V
 * At least 10 golden apples
 * Highly nutritious food, such as bread or steak
 * At least six slow falling potions
 * At least six strength potions
 * At least three stacks of cobblestone
 * An ender chest
 * Several stacks of ender pearls
 * Several stacks of empty bottles
 * A water bucket
 * Torches, to collect the dragon egg after the battle
 * Snow blocks or iron blocks and pumpkins, to spawn golems that will deal with the endermen
 * A carved pumpkin, to wear and avoid the endermen until the player have spawned the golems
 * One or two enchanted golden apples (optional)
 * One or two totems of undying (optional)
 * A trident enchanted with Loyalty III (optional)

Preparing equipments
Until the dragon is defeated, the player cannot leave the End without dying. In Hardcore mode, the player must defeat the dragon on their first visit. Therefore, thorough preparation is essential to surviving the battle.

Sword
The sword (preferably diamond) is used to damage the dragon when she's on her perch, with a secondary use of dealing with any provoked endermen. The sword should be enchanted with Sharpness IV or V, to deal as much damage as possible. Knockback is ineffective against the dragon, since the dragon is immune to knockback, but it works against the endermen. If the sword is enchanted with Fire Aspect, any endermen hit will be more difficult to deal with since they teleport upon taking damage. However, if endermen get set on fire, they will still hurt for every fire tick. Looting will also allow the player to get extra ender pearls from endermen if necessary.

Bow or Crossbow
The bow or crossbow will be the player's main weapon; both for destroying the end crystals, and against the dragon while she is flying through the air. The player should enchant the bow with Power V, to deal as much damage as possible, and Infinity, so that the player will not run out of arrows while fighting. To prevent the bow or crossbow from breaking, the player should add Unbreaking to it as well. Flame and Punch are ineffective against the dragon. Be sure to note that if the player add Infinity to the bow, they will not be able to add Mending, which will allow it to self-repair when the player collect experience.

Armor
The dragon has an attack strength of with her head. It is the second strongest direct attack of any hostile mob, only topped by the vindicator. Therefore, the player should wear a full set of diamond armor enchanted with Protection IV. Since the main way of taking damage during the fight is fall damage, Feather Falling IV on their boots is almost necessary. Thorns is also recommended, because it will damage any provoked endermen when they attack them. However, Thorns has a high enchantment weight, so be sure to add Unbreaking to the armor as well.

Pickaxe
When the player enter the End, they might spawn underground. A pickaxe (preferably diamond) will be necessary to dig up to the surface. It is also needed to break into the cages protecting some of the end crystals. If the player doesn't bring a pickaxe, it will take a long time to break both the iron bars and end stone. The player should enchant their pickaxe with Efficiency IV or V, so that the player can dig the way to the surface and break into the cages quickly, and Silk Touch is necessary to reclaim the ender chest.

Trident
The trident is used to destroy the end crystals and to deal damage to the dragon. Loyalty III is highly recommended so that the player can receive their trident after they destroy an end crystal, however this will not work if it is accidentally thrown into the void. Riptide could also be used to propel yourself into the sky and shoot an end crystal with a bow in mid-air, but should use a slow falling potion to give yourself more time to aim and to prevent yourself from taking fall damage.

Healing items
Even if the player is very well-protected, the player is likely to take a great deal of damage during the fight if they are lack of combat experience, so healing items are absolutely necessary. Golden apples are the most efficient healing item, because they provide Absorption, which will protect the player from most damage while they are healing, so bring at least 10. Potent healing potions and extended regeneration potions are recommended, but not required. Enchanted golden apples can heal players more than regular ones, but they are extremely difficult to find, so save them only for emergencies, and use regular golden apples otherwise.

The totem of undying can also be used, but it can only be accessed after the player explore a woodland mansion or stop a raid. However, it can be used in emergencies, and will prevent the player from dying. To use it, simply place it in the off-hand, and ignore that it is even there while fighting. When the player takes fatal damage, the totem will explode and cause an animation of fireworks, which will "resurrect" the player and provide them temporary Regeneration and Absorption.

Food
There should never be a time when the player do not have food with them. Bread and steak are some of the most nutritious foods possible, so bring at least a stack of either of these. Bread can also be found in loot chests that is found along the way to the end portal. The player can also bring cake, so that if they need to eat very quickly, they can just instantly place it down, and start eating without any delay. However, cake has a low saturation and hunger-filling value, so unless they have to eat at that exact moment, it is better to eat more nutritious food.

Golden apples and enchanted golden apples can also restore food points, but they are mainly used as a healing item. Eat normal food if they do not have full saturation, and only use golden apples when they take damage.

Potions
Potions are extremely useful in the fight, to enhance the performance. Because of the dragon’s knockback ability, fall damage, and the potential for cliffs, extended slow falling potions are almost necessary. Strength potions, leaping potions, and swiftness potions can also be used to boost the player's abilities during the fight.

Potions can also be used for emergency healing. Golden apples can serve as a healing item, as they will allow them to regenerate while being protected by Absorption. However, they are only effective when they take a reasonable amount of damage. In the case of emergencies, such as the health being reduced to, healing potions are recommended because they will heal the player instantly. It is recommended to turn them into splash potions, because they can be used quicker than normal potions, and will heal them as quick as the player can throw them.

Regeneration potions can helps players regenerate faster than golden apples regenerates, but they should only be used if the player take damage over time. The dragon can inflict damage instantly with its various attacks. However, if the player are at extremely low health at the end of the fight, they can use their regeneration potions to heal gradually.

Blocks
Blocks can be useful for climbing up the towers. Harder blocks, such as cobblestone, are better than softer blocks. It is recommended to use blocks on the taller towers, and just shoot the short ones. Also, the player will need blocks to build to the top of the towers that have cages around the end crystals. Alternatively, they can throw an ender pearl to get to the top.

Ender chest
An ender chest is almost necessary to have, because it can store items that the player will not use during the fight. It can only be reclaimed using a Silk Touch pickaxe. All ender chests in the world, including in different dimensions, are interconnected. So even if the player die in the End, all of the items in the ender chest will be safe. If the player make a new ender chest, all of the items that were originally in it will still be there.

Ender pearls
Ender pearls are extremely useful to have in the End. The player can use them to get up to the tops of tall towers, or if the spawn platform is away from the island, the player can use them so that them don't have to waste their extra blocks. Also, if they are high up in the air, get knocked down, and don't have a slow falling potion, tge player can use an ender pearl to teleport to the ground, and take less damage this way. If the player run out of pearls while fighting, kill a few endermen and get more.

Empty bottles
The player should bring plenty of empty bottles, because they can be used to collect the dragon's breath. It can be collected from lingering purple clouds emitted when dragon fireballs slam into the ground or when the dragon breathes while perching. Since the dragon's breath inflicts magic damage, it can penetrate the armor, so be very careful around it.

Water bucket
A water bucket is extremely useful to have when the player fight the dragon, even before the fight begins. It can be used to put out lava that is encountered while looking for the end portal. In the End, if the player fall off a tower and don't have enough ender pearls or slow falling potions, water can be used to break their fall. Water can even help them to deal with provoked endermen. If an enderman gets mad at them, dump the water at the block they are standing, and the enderman will get hurt and teleport away. The water will also neutralize the enderman, and it will start to ignore them again.

Finding the portal
All players begin the ender dragon fight with eyes of ender, because they are needed to locate and activate the end portal, found in a stronghold. To make one, the player will need one ender pearl and one sample of blaze powder. The player will need at least 30 eyes of ender, because 12 are needed to activate the portal, and the player will need a few extra eyes to find the stronghold.

Stronghold
To find the stronghold, throw an eye of ender into the air, and it will float upwards in the direction to the nearest stronghold from the player. It will then fall back to the ground, and the player have a 80% chance to pick it up and throw it again. Note that the eye has a 20% chance of shattering when the player throw it, so bring at least 15 eyes to spare. Follow the ender eyes until they float downwards, which will indicate that the stronghold is underneath the player. If the eyes direct the player to a village, the stronghold will most likely be under the village's well.

Dig underground to find the stronghold. The player might dig up into a cave or even a mineshaft, so it might be difficult to find. Place down water to put out any lava that is in the way. Keep exploring the cave or keep digging until the player see stone bricks, which will indicate that they have found the stronghold, and once the player have break in, get out the torches.

Portal room
Keep exploring the stronghold's hallways until the player found the end portal room. Collect any chest loot that have found. As soon as the player see the portal room, run in as quick as the player can, as an active silverfish spawner sits in the broken staircase that leads up to the portal. Kill all the silverfish in the room and destroy the spawner. The player can also place a stone brick stair in the empty space to complete the staircase, which will make the walk up to the portal smoother.

To activate the portal, simply insert an eye of ender into each end portal frame. Some of the portal frames may already contain an eye. Once all of the portal frames have been filled, the portal will activate and let out a loud, dragon-like roar, "reminding" that the player are about to fight the ender dragon.



Since the trip to the End is one-way, don't even think about jumping into the portal until the hotbar contains the following:
 * Sword
 * Bow or crossbow
 * Pickaxe
 * Golden apples
 * One slow falling potion
 * A full stack of ender pearls
 * Food
 * Snow blocks or iron blocks
 * Pumpkins

Put all of the items that the player will not use in the fight, such as the loot found in the stronghold, into the ender chest. Pick up the ender chest using a Silk Touch pickaxe. Make sure the player are wearing all of the armor, and instead of the helmet, wear the carved pumpkin. Holding the ender pearls, enter the portal once ready.

Entering the End
When the player jump into the portal, they will instantly get teleported to the End, giving them no time to escape. When they arrive in the End, they will spawn on a 5&times;5 obsidian platform. The platform usually generates on the surface of the island, so the player can just walk off. If it generates underground, dig up to the surface using a pickaxe, and if it is away from the island, throw an ender pearl to the island to save their extra blocks.

Get to the center of the island as quick as possible, and if they see the dragon diving at them, quickly jump out of its way. Drink a slow falling potion in case of getting knocked off. Before fighting, they will need to do a few things.

Terrain
Because falling into the void will kill the player and lose their gear, the player should stay as close to the center of the island as possible, or at least inside the circle of towers. The player should also avoid any holes in the island. Due to the dragon's knockback ability, they should stay at least 30 blocks away from any edge. If they get knocked off, they should immediately throw an ender pearl back up. If they are quick enough, it is possible for them to teleport out of the void and back onto the island. Chances are better if the ender pearls are held in a slot of the hotbar that the player can instantly access, or if the player have drank a slow falling potion.

Backups
It is highly recommended to bring backups with the player, because they will deal with the endermen while they are taking on the dragon. They may also clear the area in the middle of the island so that the player will have more space to move around. Snow golems or iron golems make the best assistants, because they have stronger and more effective attacks than tamed wolves. The only difference is that iron golems will actually attack the endermen, while snow golems will only chase them away. Bring enough materials to spawn at least five golems.

Until they have spawned their golems, wear the carved pumpkin to avoid the endermen. The best time to spawn them is when the dragon is resting on her perch, as she will not attack players or iron golems. The player should also spawn them to the sides, in case she releases the dragon's breath.

After the reinforcements are spawned, reorganize the inventory so that the hotbar contains the following:


 * Sword
 * Bow or crossbow
 * Pickaxe
 * Golden apples
 * One slow falling potion
 * A full stack of ender pearls
 * A full stack of extra blocks
 * Food
 * Bottles

As soon as the hotbar is organized properly, quickly take off the pumpkin mask and put on the helmet. Now the player can begin the epic showdown with the dragon.

Destroying the end crystals
Destroying the end crystals is a key part of the battle, because they heal the dragon. With all of the crystals active, the dragon will recover faster than the player could ever hope to damage it. It is possible to defeat the dragon while some crystals remain, provided the dragon spends enough time away from them, but it is recommended to destroy all of them. One end crystal sits atop each obsidian pillar. There are usually eight to ten towers of different heights arranged in a circle around the empty exit portal. Crystals on the tallest towers may be difficult to see, but the healing beam they emit when the dragon is nearby will give away their location. Try to destroy a crystal while it is healing the dragon, because the dragon will take damage if this is done.



Shooting
The easiest way to destroy the crystals is to shoot them with a bow or crossbow. Position the player so that they can see one at least partially, aim the shot just above the crystal from the view, and adjust the aim if needed. When destroyed, the crystal will generate a massive explosion. Be aware that they may have destroyed the crystal, even if the player have not seen the explosion. The player can know that it has been destroyed by the explosion sound. If the bow does not have the Infinity enchantment, snowballs could be used to save on arrows. The player should always shoot the crystals on the shortest towers, because they are the easiest to shoot and are much quicker to shoot than climbing to the top.

Climbing
Attempting to climb to the tops of the towers is extremely dangerous. Even if the player build up using a dragon-proof material, such as end stone, the dragon can easily knock the player off while they are climbing. However, it is necessary to get up to the top of the caged towers, because shooting them from the ground is ineffective.

It is quicker and safer to use ender pearls than the player's extra blocks, because the dragon may knock they off while building up. One trick to measure the ender pearl shot is to fully charge the bow or crossbow and shoot an arrow just over the top edge of the cage. If they throw an ender pearl at the exact same angle, it will strike one block below the arrow's trajectory, teleporting the player to the side of the cage. Break into the cage with a pickaxe. If they have strong enough armor and are affected by Absorption, hit the caged crystal with a sword. Otherwise, build a few blocks away from the crystal and shoot it with a bow or crossbow.

Once the caged crystal has been destroyed, don't go back down, because some towers are taller than the caged ones. Build a few blocks above the caged tower, and shoot the taller ones with a bow or crossbow. If the dragon knocks the player off, and they are not affected by Slow Falling, place water or use an ender pearl to break their fall. Throw an ender pearl back to the top of the caged tower, and try to shoot the taller ones again. The player could also throw a pearl to the tops of the tall towers and destroy the crystals with a sword. If the player are on the tallest tower, they can check how many crystals have been destroyed and how many remain. It is also a good spot to snipe the dragon.

Killing the dragon
If the player are not sure that they have destroyed all of the crystals, let the dragon fly away. If the player see a healing beam, they will know that there is a crystal left. Once the last crystals have been destroyed, the player can start to attack the dragon. The player can also swap out the extra blocks with a water bucket, because they will not need the blocks anymore. There are many ways to attack the dragon, but there are many things to watch out for, too.

Healing
The dragon has three types of attacks: body attacks, the breath attack, and dragon fireballs. The more crystals the player have destroyed, the more often the dragon will attack them. It will inflict damage if it hits a player with its head, but its wings will only inflict  damage. The dragon's breath will inflict damage per second. The dragon has an extremely high knockback ability, and can throw players into the air to fatal heights, so they should keep drinking slow falling potions when they run out. They will make players immune to all fall damage.

Keep track of the health at all times. If the player take at least damage at a time, hide behind a tower and eat a golden apple. Use healing potions if they are on the brink of death to recover instantly. If the totem of undying in the off-hand goes off, and they have another totem, quickly throw it in the off-hand and resume fighting immediately.

Dragon's breath


It is extremely useful to collect the dragon's breath during the fight because it can be used to make lingering potions, which are recommended to have if the player want to fight the dragon again or the wither.

To collect the dragon's breath, wait for the dragon to perch and do its breath attack or shoot a dragon fireball, either of which will puff out into lingering purple clouds. The only difference is that the dragon's breath comes instantly from the breath attack, whereas the player must wait for the fireball to slam into the ground. To collect it, simply hold out an empty bottle and scoop up the clouds the way the player would fill a bottle with water. However, they should avoid making contact with the clouds, because they will hurt players. The armor cannot protect players from damage from the dragon's breath, because it counts as magic damage. The dragon's breath is stackable, so the player should collect as much as possible.

Attacking
While the dragon is flying, the player can shoot it with a bow or crossbow. However, the dragon is really hard to shoot, because it can fly extremely fast, and the shot will miss if they don't line it up properly. It is recommended to shoot at a spot in the dragon's fight trajectory, because then it will fly forward enough to get hit by the arrow. Try to mainly shoot it in the head, because the dragon takes the most damage on its head.

The more crystals the player have destroyed, the more often the dragon will dive at the portal. When it's hovering over the portal, it is immune to arrow damage, and the player will be forced to use a sword. It is recommended to get as many critical hits as possible, because they can inflict more damage this way. It is recommended to drink a strength potion, because the dragon may dive at the portal for each time it circles around the towers, and the player will inflict more damage using the strength the potion provides.

The player will begin to notice a pattern in the dragon's behavior after a few minutes. It will dive at the portal once for every circle, so they should make sure that they always have the strength from the potions when the dragon perches. Remember the pattern of the attacks, so that they will be efficient for the rest of the battle.

Once damage have been inflicted, the dragon will die and drop four unmatchable rewards.

The rewards
When killed, the dragon will float upwards and disintegrate, with bright purple beams of light erupting from its body. It will then explode and cause a faint sound that gradually fades away into the infinite darkness of the End, leaving almost no trace that it was ever there. Four precious rewards will then appear.

Experience
After the dragon dies, a colossal amount of experience orbs will rain from the sky. These orbs can take players from level 0 to level 70, which is worth 12,000 experience points. Some of the orbs may fall into the portal, so run a few laps around the portal, and then sneak on the rim of the portal to grab some more. Since it takes progressively more experience to gain a level at higher levels, they will have enough to make over ten level 30 enchantments. The player don't have to get enchantments that they will use; they can simply enchant extra equipment to use as a backup set. The best time to enchant extra equipment is as soon as the player go back to the base, in case they have died and lose all of the precious levels collected.

Dragon egg
The second reward is the priceless, one-of-a-kind dragon egg. It sits on top of the portal when it first appears. However, it cannot be broken directly, as the egg will teleport if the player attempt to do so.

Instead, touch the egg once and let it teleport to a block of end stone. If the player can't find it, follow the purple teleportation particles. To pick up the egg, place a torch two blocks underneath it, and break the end stone block it is sitting on. Since the egg obeys the law of gravity, it will fall onto the torch and break as a collectible item.

Alternatively, if the player have a piston and a lever, place the piston facing the egg. Place the lever on any block touching the piston, because the piston will extend no matter what block the lever is on. The egg will still break as a collectible item. To prevent the egg from falling into the portal, cover the portal with blocks.

If the player use either of these strategies, they will get the dragon egg successfully. It currently has no use other than as a trophy to say that the player have defeated the ender dragon, but it can serve as a beautiful decoration or an addition to a trophy room at the base.

End gateway portal
Perhaps the biggest reward of defeating the ender dragon is the end gateway portal, which generates after the dragon dies with less than twenty portals generated. The player can only enter it through the use of ender pearls because it is too narrow to walk through. This portal is sometimes considered the only reason to need to fight the dragon, because it gives the player access to the End's outer islands without bridging, which is the only place where the player can find end cities, shulkers, chorus trees, the elytra, and the dragon head.

Exit portal
Since the fight takes place in the End, the most important reward is the exit portal, which is the only safe way back home. It appears all the time, but only activates when the dragon is killed. The portal looks like a fountain made of bedrock, with torches on the sides, and the "water" of the fountain is made of end portal blocks that will take the player back home.

When the player enter the exit portal for the first time, the End Poem is shown, telling them that they have basically "completed" the game. (The End Poem can be skipped by pressing in Java Edition or tapping "Skip" in Bedrock Edition.) They will then respawn at the Overworld at their respawn point, which can be the world spawn point or the last bed the player have slept in. The player can then safely return to the base.

The rematch
To have a rematch with the ender dragon, the player have to respawn it using end crystals. To make one, the player will need seven pieces of glass, an eye of ender, and a ghast tear. The player will need to go to the Nether to get some of these materials.

To respawn the dragon, place four end crystals on each side of the exit portal. The crystals that is placed will instantly deactivate the portal, shoot beams at the tops of the towers, and reset the crystals and cages on the towers. Afterwards, all of the crystals will shoot beams into the sky in harmony. The player will hear an extremely loud roar and see a massive explosion, which will resurrect the dragon and begin the fight again.

To respawn the dragon, place the end crystals in the configuration shown in the image below.



There is no real reason to fight the dragon again, because subsequent dragons will drop less experience and will not drop another dragon egg, so the only reason to need to fight again is to produce additional end gateway portals or to obtain more dragon's breath. The player need to prepare the same equipment all over again. However, if the player do want to fight again, the player can use new equipment that cannot be used in the first battle.

Redstone tactics
Once the player have defeated the ender dragon, they can safely build a redstone circuit in the End. Using dispensers, the player can shoot projectile, such as arrows at the ender crystals. The player want to fire the dispensers quickly, before the ender dragon damages the redstone circuit. To do this, the player need to place a button near the exit portal and connect it to the tops of every obsidian pillar.

Materials

 * Circuitry
 * 1 button
 * Half a stack of redstone repeaters
 * Several stacks of redstone


 * Weapons
 * 2 end crystals
 * 10 dispensers
 * 10 arrowss, snowballs, or eggs.


 * Building material
 * At least 4 stacks of end stone
 * A stack of obsidian
 * A pickaxe

Setup
Place the button near the portal. Create a path of redstone from the button to each obsidian pillar. To save redstone, the player can start with a few paths and branch them out when they get close to the pillars. Remember to place a redstone repeater every 15 blocks.

For the circuit to reach the tops of the pillars, the player will need to place solid blocks that lead to the tops. The ender dragon cannot destroy end stone of the structure, making the circuit easier to repair between battles. Place the redstone on these blocks.

In certain places, the player should use obsidian instead of end stone. Near the tops of pillars, the end crystal explosion will damage the structure if end stone is used. Additionally, the player should use obsidian instead of end stone when placing a repeater (i.e. place the repeater on obsidian instead of end stone). This includes repeaters placed at ground level; the player can mine a block of end stone and replace it with obsidian. The reason for placing repeaters on obsidian will be explained later.

Once the circuit is complete, the player have easy access to the tops of the pillars, so they can begin to arm the dispensers. There are 2 methods:
 * 1) A method that is less efficient, but works on all end crystals.
 * 2) A method that is more efficient, but does not work on crystals that generate iron bars.

To avoid using method 2 too many times, the player can look at the configuration of the layers of each pillar. Only pillars with the configuration below generate iron bars.

Only 3 pillars have the configuration above, so the player will only need to use the second method 3 times, even if they do not know which pillars generate iron bars. However, if the player do know, they only need to use the second method twice.

For the first method, place the dispenser face-down, above where the end crystal should be. It is easy to tell where this is, as the end crystal will sit on a block of bedrock. Place the dispenser high enough that can be standed on the bedrock. Then, put a projectile in the dispenser and connect it to the circuit.

For the second method, the player will have a second end crystal on the edge of the pillar when the iron bars regenerate, the player want the second crystal to be outside the cage. Before placing the crystal, place a dispenser face down above where they want the crystal. Similar to the first method, the player should be able to walk under the dispenser. Put a projectile in the dispenser and connect it to the circuit.

Activation
The player should activate the circuit when respawning the ender dragon. As soon as the player place the last end crystal. go to the button and do not wait for the dragon to respawn. Press the button when the dragon respawns. At this point, all of the end crystals will be in place and can be destroyed. The dispensers placed using the first method will fire at and destroy the corresponding end crystals. The dispensers placed using the second method will destroy the crystals that the player has placed. The explosion will destroy the naturally-generated crystal, destroying the iron bars, if there are any. In both cases, the explosions will destroy the dispenser and the nearby redstone.

Reusing
The player will need to go to the top of each pillar to replace the dispenser, redstone, and when they are using the second method, the end crystal. Additionally, the player should thoroughly check the rest of the circuit. If they see a gap, it means that the ender dragon flew through the circuit during the previous battle. Obsidian marks the places in the gaps that had redstone repeaters. Put the new repeaters in the same spots to ensure that the circuit is working.

If the player intend to continue respawning the ender dragon for a large number of times, they may want to obtain the resources that is renewable. They should trade with villagers, as librarians sell the glass that is used to craft end crystals and clerics sell redstone that is used for the circuit.