Patriarchs spawn every 20-30 sec near the tower and will run to him. If they aren't intercepted, they will cast a heal on Zalak, and then detonate, doing large AE Direct Damage. Set a main assist to target these groups while they are inbound and fight them atleast 30 meters from Zalak.
Also has an astrologer, acolyte, and a few royal guardians attached to King Zalak.