Boku Ni Wa Onee-Chan Ga Sannin Imasu (Jisshitsu) - Ch. 15

[MangaDex]

 

[CrimsonSix]

Just read up on them all. Certainly an... interesting concept.

 

[ScryedParadox]

The biggest twist.

They have some situational awareness... Some, because based on all the other chapters/pages, they clearly have no qualms about doing all these shenanigans in public.

 

[Kyuketsuki]

Suffocation, to die by oppai.
In Valhalla, you shall be greeted with drink song and glory.