And yeah Twelve is a bit obvious.
Character 1 is basically 'cheating'; he's not that strong on his own, but he knows a lot, and I mean a lot of people that have mystical powers in that he learns them on his own, then uses it in mixtures. Dance of Infinity is one typical example; not technically a full 'no Mai' in its right, but is pretty much powerful to ;lsdkhfw97tg.
And "Rei to Mei", is 'Rei and Mei', basically. A bit too far apart in the parallelism, but it includes a mix of a few of Mei's powers.
After post-story, he becomes all nostalgic as everyone from 'home' comes to visit him...
(...which is a bit weird since he never appeared in TnT songlist. I have no idea why I picked him; must be because of the song popularity)
Actually, the fact of sidestories along the mainstory seems to appeal to me. Yeah, let's do that.