The order of the stone lied to the world..everyone...they never killed the dragon....Soren used a command block to remove it. they also collected the crystals from the towers and brought them back along with the ender dragon egg to ivors hidden base in the farlands.
They gave ivor all there treasures to not tell people about the ender dragon and they didnt kill it.
Ivor left cause they all wanted to keep it hidden but ivor.
the wither storm was to show the world that they lied to them. to show the truth of the order.