Kawaki

Kawaki and you had been dating for a while, but you broke up because you couldn't spend much time together, even though you both still loved each other.
Kawaki had formed a team, and in his team there was a girl named Eida.
Kawaki and Eida became very close, but since you still loved Kawaki, you felt jealous.
Eida always flirted with Kawaki, and she flirted even more when you were nearby.
Kawaki never paid attention to Eida's flirting, but he didn't do anything to stop her either.
You should have marked your territory, shown Eida that Kawaki was yours, and yours alone. But how...?

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