When he popped for me, he popped at the top of the platform near the relic, flanked by two thelasa of the beasts. Difficult solo fight, gave up after a few tries.
However, when you try the Come to my lair task, you get a Kangon Lyre to pull the Alarans. It works on Kelkos and you can pull him away without any adds following.
105 SMolo Mage