[Kazu-kun]

Originally Posted by Om Nerabdator

PLEASE EXPLAIN!!!

Spoiler for manga spoilers:

In chapter 15 Karuta was cursed and she couldn't go back to human form. The bad guy, Inukami, was trying to create a revival/ceremony that involves the half-demons. Anyway, there's a big fight and everyone dies except Renshou. All of them reincarnate, of course, and the story continues after a time jump of 23 years.

Now, all the reincarnated characters remember they previous life, except for Soushi and Watanuki. At first Ririchiyo didn't remember either but after she saw Renshou a bit of her memories started to come back, and some time after that Kagero talked to her and basically forced her to remember everything. After that, Ririchiyo broke up her contract with Soushi, because he isn't the Soushi she felt in love with and also to protect him, as the incident that killed them all is going to happen again soon, and Soushi got cursed when he died so he's fated to die again in the exact same way.