Otr comes with Regin, there in the room that looks like the figure 8. Both are caster/healer types nukes do on average 320, when pulled they spawn 3 blue cave spiders, 4 Red/Purp skelly at least 2 will be grapeling but die with 2-3 Lifetaps from Dark SM
Did this with a War, Sham(Bot), SM w/ML9 Pet Strat: Had warrior pull, aoe mezed the skellies that spawned (they had been chain grappeling him) Cast ml9 and sent pet on Otr, took down skellies and had warrior on Regin. Bot group-healed and both droped easly.
Regin changed forms every now and again couldn't tell difference though saw Human, Bear, Spider, Vendo