As with many other survivors across Harran, notably in the quests Fan Zone and Where's My Mother?, Umar has become isolated, and has grown into a crazed, violent individual through the course of the outbreak. He is killer and a cannibal who has murdered several of the building's residents, including Dooley's dog Mike and his father. Upon seeing Crane, Umar immediately attacks. He resides in a locked basement for apartment unit 3, in which he keeps several corpses and various cuts of meat, along with the carcass of the dog Mike.
He notably yells 'Meat!' as he attacks, implying he intends to consume the player character after killing them.
Judging by the letter and voicemails uncovered during the quest, it is likely that Umar has killed multiple residents, including Samir (the superintendent), Cemal, and Dooley's father.