Minecraft Dungeons:Ancient Guardian

The Ancient Guardian is the final boss of the Hidden Depths DLC. It appears similar to the Elder Guardian but is purple colored and has a pink eye. it has been corrupted by shard from the Orb of Dominance, hence it has very End-like appearance like any other main bosses.

Appearance
The Ancient Guardian is an oversized Elder Guardian with a predominantly dark purple body with lighter purple stripes on its back. All of its spikes are a light purple to white in color and its eye is a light purple in color with a white iris. On its back is a few patches of algae, coral, and seaweed, with some on its tail. Its face is full of cracks and a long scratch is seen across its purple eye.

Behavior
The Ancient Guardian is not the most fair and a rather tricky boss in the game as it would swim away from the arena to avoid damage. On top of that, it has three attacks it uses every so often:

Ancient Beam
It is capable of launching a beam at the player, which behaves the same way as its weaker counterparts.

Ancient Summon
It can summon guardians whilst keeping out of the arena.

Ancient Mines
It can summon landmines in the arena which explode on contact

Vulnerability Periods
It can't get stunned like other bosses, but it will come into the arena every so often, allowing the boss to take melee damage.

Trivia

 * At one point in a Tweet on Twitter, the developers referred to the Ancient Guardian as being the corrupted master of Guardians and Elder Guardians.