The clone displayed a "flickering" ability much like Gray Boy's or Scapegoat's, which he used to conjure costumes and tools for himself and a clone of Alexandria, as well as to heal injuries and free himself from bindings. He also used aerokinesis, that allowed him to create vacuums, make sounds carry, and fly. Eidolon speculated that Ignis Fatuus wasn't affected by his slow loss of power, and perhaps if Glaistig Uaine claimed his power, she wouldn't be as well. Skitter, however, speculated that Ignis Fatuus was enhancing his power using his variant of Scapegoat's power.
He created an armored costume for himself to mirror Eidolon's - a black hood, loose black sleeves and a pale red-orange glow emanating from each opening.
- He was only named in the chapter tags. The term ignis fatuus means a will-o-the-wisp - a malevolent ghost that leads travelers astray - or more generally something that misleads or deludes; whereas "Eidolon" means an idealized image or phantom of a person.
- Had Wildbow not received more donations, Ignis Fatuus would have had a larger role in the story, serving as a catalyst for Skitter investigating the setting's lore earlier than she did in the canon story-line. Consequently, Worm would have been far shorter.