Eidolists will stay in one place until they are damaged, in which they will attempt to fly towards the player, going through blocks and teleporting periodically. Once provoked, they will release lightning orbs and ice balls that emit ice shards. Both attacks are very similar to those of the Lunatic Cultist.
- Eidolists do not deal contact damage which opens them up for more aggressive players who struggle to close distance without suffering heavy hits of damage.
- For this reason, true melee weapons are extremely effective against this enemy.
- Only one Eidolist can be alive at once.
- The Bestiary entry for the Eidolist: "Highly skilled in the art of spellcasting, these mysterious creatures seem to stand guard like sentinels in watch over something. Approach one close enough and you may be able to make out garbled whispers."
- Judging by their appearance and behavior, they seem to be a Cultist partially transformed into an Eidolon Wyrm.
- The Eidolist still resembles an old sprite of the Eidolon Wyrm, which was heavily based off of the Ghost Leviathan from the aquatic exploration game, Subnautica.
- In previous versions of the mod, Eidolists used to spawn in the Dungeon as well as in the Abyss in Pre-Hardmode. However, they would not drop the Eidolon Tablet at this stage of the game.