The Order of the Stone is the name of a group of legendary heroes in Minecraft: Story Mode. The title previously belonged to Soren the Architect, Ellegaard the Redstone Engineer, Gabriel the Warrior, Magnus the Rogue, and (formerly) Ivor the Brewer. It now currently refers to New Order of the Stone after Episode 4.
The Old Order of the stone (Soren, Ellegaard, Gabriel, Magnus, and formerly Ivor) became famous by killing the Ender Dragon when in reality Soren vanished it using a Command Block. The New Order of the Stone was made famous after Gabriel announced that The Old Order 'killed' the dragon by a Command Block.
Ellegaard/Magnus dies (determinant) in Episode 4, therefore Gabriel's quest given to Jesse about reuniting the Order could never be completed.
The Order before vanishing the dragon
