Violence / Gore: Natsuki is violently tsundere towards Seki, punching him or throwing a trash can in his face. There is usually no justifiable reason for any of this and some blood is seen. There's an attempted suicide by the person wanting to throw themselves off a cliff.

Nudity / Sexual Content: There's a couple of "pervert" and boob jokes. Seki's fly is down at one point without his noticing and a bunch of the boys are seen in speedos at the pool. A bit of a spoiler related to the previous point Spoiler: a close up shot of Seki pulling his phone out of his speedo, which he put there since it was "the only pocket he had" during the swimming lesson. The kids go to the beach and are in swimwear.

Theological Themes: Characters either naturally have or can get telepathic/psychic powers. Some of these appear to be linked to animal familiars or objects. Spoiler: There's also time travel, which isn't necessarily theological but seems to be linked to the telepathy.