
Frantically pantomiming behind a one way mirror
we've got:
the anime adaptation came out ~5 years before Utena; what you realize watching it is that Ikuhara took a lot of inspiration from it, and that in some respects he actually toned down just how fucked up everyone is. the best description I've heard is "Oniisama e is a mystery horror anime, and the mystery is why the fuck are these girls like this"
(also, I do think Oniisama e is interesting to have in your reference pool while watching g-witch, even if you've already seen Utena - there's some specific character moments with Suletta where her vibes aren't really Utena at all, but are 100% Nanako)