[Cruzz]

Originally Posted by Cardiac Glycoside

Then I need a little help here. I remember when I first beat Niwe I used Hakuoro. Is it something like that?

Yes, exactly

Spoiler for Character combinations:

Karura x Suonkasu (girly boy in a cape throwing daggers, hasn't shown up in the anime)
Kamyu x Mutsumi (hasn't shown up in anime yet)
Touka x Orikakan
Uruto x Dii (angel boy)
Dii x Kanhorudari (berserk king, hasn't shown up in the anime)
Eruruw x Nuwangi
Nuwangi x Sasante

Bonus characters:
1. beat the third final battle with anyone
2. beat the fourth final battle with anyone
3. beat any route with first special character
4. beat any route with second special character