Perhaps something like the
Spells Enhanced - Crown of Madness mod might be worth looking into?
Making Crown of Madness have no concentration or save means you can just cast it on yourself and go auto-pilot for 10 turns (Also, opens up more weapon options than just flail)
Honestly, could make for a funny Zerker build. Enrage, go mad, then start swinging and hope everyone else falls before you do.
