While the Red Devil itself does not cause much contact damage, its trident attack is capable of dealing large amounts of damage even to players in Hallowed armor, Chlorophyte armor and Turtle armor. The tridents are similar to the Demon's scythe attack, but do more damage and do not accelerate.
The Red Devil is immune to the On Fire! debuff.
- The Red Devil may be a subtle reference to VMFA-232, a US Marine fighter attack squadron nicknamed the Red Devils, as their emblem looks very similar to the appearance of this devil in-game.
- The Red Devil may be also be a reference to the Red Devils of the NES title Ghosts and Goblins, who are also notorious for being extremely hard to kill for less experienced players, and both appear to look quite similar.
- If you defeat any of the three mechanical hardmode bosses before hardmode is enabled (through use of the appropriate summon items), this will allow for the Red Devil to spawn at any time. If you don't want them to appear, avoid fighting the hardmode bosses pre-hardmode.