Kathra'Natir was a dreadlord who was banished by Alodi, the first Guardian of Tirisfal and the Council of Tirisfal, over 3000 years ago. Meryl thought he was gone, banished, too weak to trouble Azeroth again, but he returned when Vendellin Soulfire cast the Mark of Kathra'Natir over Valeera Sanguinar, allowing him to possess her. Since then, the dreadlord has been inside Meryl, forced to do his bidding, and sometimes helping him with his own abilities. Eventually, Meryl thought the influence of the demon too much for his relationship with the New Council of Tirisfal, so he left.