[@Demon Shinobi]
[quote=@Spanner]
 If you're really thinking of changing Tsumiki, I'd recommend using Belial's clan. Their unique ability is so freaking OP that it even hurts, turning anything the other party uses worthless as long as they retain enough power to do so.[/quote]

On that note, I actually think that Tsukimi is just fine as he is. In terms of strength, the only one decisively stronger than he is Siegfried. Everyone else has their own strength and abilities, but they all have a caveat of some sort.