Very easy. My team struggled the first time we attempted him but the next time we crushed him hard. Ideally you would have a bubble titan and a hunter but I'm sure it's possible without those two helping out.
The best tip I can offer is taking time on the damage section. If the one who has the bubble shoots the adds too quickly you won't have time to do enough DPS. Wait until the counter is at a couple seconds left then shoot another add to refresh the bubble. The first time we attempted the fight we shot the adds too quickly and didn't have enough time to kill him. Hope this helps.