User blog comment:Koishi-Komeiji/Tsukasa Amane/@comment-32751919-20191004153518

She providing Tsukuyo's NP, Tsukuyo makes her hit harder. Her second skills and her NP could make sure that her sister won't die from buffed attacks from enemies, at least, most of the time.

But the main point is while she works together, it's can be more than 50% sure that she will get a lot of starts (if not use Arts cards lol). Cuz her sister can generate stars and she has a stars gen on the justified level. (Did I mention, her sister has 3 Q cards?)

They help each other, such a harmonic relationship...