The older sister, Sakura Yuumi, is played by Erena. If you watch our subs, she should be somewhat familiar. She's been in:
Kamen Rider Kabuto episode 12
Engine Sentai Go-Onger 34 (Played Saki's older sister)
and Kamen Rider Ryuki Episode Final as Miho's older sister
Add OOO to that, and that's quite a history
I kind of like the little animations that they've done in the past couple of episodes. The Love Combo was particularly funny
Preview