Ragged Casters attack by firing three homing projectiles at the player which inflict the Blackoutdebuff. Blackout is a stronger version of the Darkness debuff, greatly lowering the player's light vision. Ragged Casters teleport to a different location on-screen after a period of time and have no delay between teleporting and attacking.
Unlike the other Hardmode Dungeon casters, the Ragged Caster will not teleport immediately after being hit.
Ragged Casters can only teleport onto solid blocks. If there is no valid place to teleport to, they will remain in the same location.
They are only able to teleport while resting on a solid block.
In Expert Mode, Ragged Casters have a 0.13*1/800 (0.13%) chance to drop two Spectre Staves at once. The chance to drop exactly one Spectre Staff is 7.25*29/400 (7.25%), hence the chance to drop at least one is 7.38*59/800 (7.38%).
Weapons that stick to enemies (e.g., the Piranha Gun) are exceptionally useful, as they remain on the Ragged Caster after the teleport.
Weapons that deal high damage in single hits are effective against Ragged Casters. Weapons that fire multiple projectiles simultaneously may be able to land multiple hits before they teleport as well.
Weapons with homing capacities or minions can continue to track Ragged Casters after they teleport.
The Bestiary entry for the Ragged Caster: "With their cursed magic, the members of the Ragged Brotherhood leave their victims helplessly lost in utter darkness."