So far I'm on level 8 for all 3 dungeons. Fear and Life aren't too bad, in my opinion as long as you can keep up a thorn or cyclone shield, you'll do alright damage wise. I also use Navigator Eddie for healing the team and taking down that force shield, and as long as he's invisible, he can keep supporting the team. It's great on fear when he uses charted course and you have thorn sheilds, the Dragon King's attacks just tickle with those buffs. But it's mostly the negative effects you have to worry about. Obviously immunity plays a big role in this unless you can stay invisible, I haven't tried my Pharaoh dog but I'll do as was suggested. I can imagine that the Garden of Life boss works the same way if you find someone who can lower the King's magic and boost your own resistance, while applying a cyclone shield. But the Dismay is very difficult because of how many hits the force shield needs before the passive resets. I can imagine bringing in as many multi hit attackers as you can to make it work.