The Easter Dungeon is split into two stages and two level categories:

Small: Level 50–95

Large: Level 95+

A Dungeon Pass is required — buy it from the Dungeon Information Window.

Stage 1: Break the correct stone -> Defeat Mini-Boss -> Break another stone -> Destroy Forest Branch (get Magic Key) -> Use key to open door

Stage 2: Break central stone -> Kill monsters to weaken stone -> Repeat process -> Use keys on Owl Statues -> Defeat Mini-Boss -> Kill monsters again (get final key) -> Use last key -> Defeat Sylvanus