I have not beat him yet, but I have fought him twice and I find myself hiding behind him while my minions work on him. I think he is worthy of having some rear end defenses, that tail does look intimidating 
I am failing because I don’t know know the fight, but I can say he does feel “easy” when you know you can hide behind him. I failed to his breath because my golem died and my hands went “oh shit I am an old boomer and can’t work buttons!”
Then his bomb blast because I stood in the circle… never stand in the circle kids, LOL!
Funny that I dodged that at least 12 times and then a voice in my head said "hey it isn’t hurting you, just stand here… WRONG!
Then again, my golem draws all the fire, so maybe it’s different with other characters?
Pretty confident I will get him tonight, I have all the pieces and have done some more research.
Love your game and am looking forward to many, many rerolls!