Talk:Episode 38 - Aikatsu New Year!/@comment-24649122-20161217010836/@comment-24848025-20161223131141

In all technicality though, S4 is not the only unit in the school. There are actually two other units that are around as well -- M4 and the Admins.

That being said, one does have to wonder if this is a storyline decision or a directoral decision - one could say BNP is not doing non-roational permanent units like Tristar & Soleil because that could hurt the show in the long-term because fans may get too attached. That could be espeically bad when members from AIKATSU ☆ STARS! are added or graduated (like say, if Ruka & Miho were to leave) and vocal replacements have to be found for characters instead of being able to be written off. Storyline-wise, it could be for the previously mentioned reasons that having a non-rotational permanent unit could be bad for S4 (and thus the school).