I have I and II as well. In I, all that's left to do is kill Prinny Baal but I think that's too high of a goal for me. And I got bored looking for all of the maps in II. =/
In I, my favorite character is my Lv. 1500 Galaxy Skull. I transmuted him tons of times, and got the Rank 40 staff for him (I can't remember if it's leveled up or not), and after all that he can do 1 million damage per shot.
I know now that sword users end up stronger anyways with the Yoshitsuna, though, which is kind of lame. (Divine Majins are silly...)