McCairn is an elite soldier and a member of the Murder of Crows, a team composed of Jacob Kane's old partners in the special forces. He is an expert at mixed-martial arts, though he prefers truncheons and bladed weapons in combat. He also bears some proficiency in the fields of forensics, archaeology and philosophy......and may or may not labor under the delusion that his Irish accent makes him a hit with the ladies. He trained Batwoman and Hawkfire along with the rest of the Murder.
Sean McCairn was created by J.H. Williams III and Haden Blackman in Batwoman #0.