Rei and Kazuomi met by chance at a bar they frequent.
As they chatted, the two grew closer,
and their shared views on love led to a physical relationship.

A few months later,
Rei began to feel attracted to Kazuomi as they spent time together,
but was unable to end their fruitless relationship despite being troubled by it.
Coincidentally, this all changed on Rei's birthday.
Instead of congratulating her, Kazuomi told her,

"Rei, you're my tool for revenge."

Rei was confused when she saw Kazuomi's true nature.