Brother 4 was a high ranking Brother of the Church of Besainted Pelagius. It was an affiliation that got him killed however, assassinated along with Brother 7 by an invisible attacker. Although his death did not faze the higher brothers, the lesser brothers admitted that they found that his screams were somewhat disturbing.
References[]
Gillen, Kieron (w), Hector Sevilla (art). "A Ghost Story." In StarCraft: Frontline: Volume 2 (paperback binding), pp. 122-169. Tokyopop, January 1, 2009. ISBN 1427-80831-7