witeslice, mah man, i know nothing of majin builds except from what i see in game. Based on this build, you have chosen and maxxed all of my personal favorite skills. the giant pink ball, the kameha, and the ki blasts. sounds good to me. sorry i cant be of more help, although awhile back someone posted a link to a korean forum with builds for each class, you might wanna dig that up and reference it with your build. it was several months ago so its probably a little outdated, but it would give good guidelines.
-I have to go with Inuyasha on this one, the 1/3 for Passive isn't worth it, infact the chance of crit from that skill is still low. I put that one point from the passive crit into Unbreakable elastic.
I'm no Majin expert, but the rest of it seems pretty solid.