The mark on Fuuta's face is more healed now. Probably each generation of reincarnation it heals a bit, and in the present it's almost fading. What if that is the symbol of the hate and grudge they hold against each other, maybe with the passing of years that hate is actually fading and they could find a compromise. The past selves influence the present people a lot, and the reason why Fuuta doesn't hate Kouko yet is probably because he hasn't seen enough, but he might come to hate her too in the future. The spirit circles are something only the present owners carry apparently, Kouko maybe had it for more than a generation though. "Fate, our bonds... people we know, our circles maybe"