Known spawn location:
Every 45 seconds, casts "Iremaw's Attention" on random target and buffs itself with "Scent of Blood". If Iremaw moves 250+ range away from its current location at the time of cast, it switches its top aggro (and holds it) to whoever has "Iremaw's Attention" on them.
The "Attention" debuff can be cured, but causes "Iremaw's Vengeance" to be triggered on the curer.