⚠️ WARNING ⚠️ managed to take him down as a duo but died in the process. When I ran back (very short run) he was already despawned, and so we had to kill him twice. Be aware of this.
This guy was quite the challenge. He has about 30K hp, is quite tanky and also hits me as a tanky warrior with decent mitigation for 250-350. He also has a relatively fast (maybe 1.5 sec) cast flame spell that hits for over 1000 damage! Therefore it's super important you have a kick order to never let this thing go off. Luckily it is a pretty short range, so if you're fast you can just run away while he's casting and max range it, but that's tough to consistently pull off in a fight. Just a tip that could save you in a pinch.
It took me (58 warrior) and a 57 rogue about 5 tries before I finally got the item. With a healer, it would have been so much easier.