It would be too weird for this to be a coincidence so the current thinking is:
She found out that the MC is LL's son and wants to be with him based on an obsession that LL killed her sister and freed her from her parents. So she finds out the MC is dating Youko and forces her father to hire Youko, just so that the MC shares with him his plan to get Youko out of the business and scam SKALL. They steal the money, get caught and Youko gets killed which works out in her favor since the MC is now single. They manage to beat the leader of SKALL after he tried to kill them both, and once this is all over, she makes her father kill himself in their old apartment, just to show the MC?
This is quite the long con she's been working on. Guessing his other personality has more to do with this whole situation than we originally knew?