A Poison-affinity character working for Aidan Flamberge in secret. A girl who is biologically immortal (and is stuck at age 21), Caoimhe was born somewhere on TAC (alfa can choose where) in the 1900s (Pteri can pick her b-day). She works as a spy, and as Aidan's servant, wears a uniform of some kind; her face is always masked, her hands always gloved. She prefers to use magic, naginata and plasma rifles.

Her sister Cairistěona died in 2000, at Evan O'Neill's hands.