I Got Reincarnated as a Cultist Mob in an Eroge Full of Maniacs with Death Wishes Volume 2

The “Mobile Fortress Plan” — a project to surgically transplant body parts from the cult’s excecutives into Oakley’s own body — is starting to look alarmingly feasible. But for Joanne, the thought brings more than a little unease...
Determined to destroy the Aros Temple Cult from within, Oakley proposes the Mobile Fortress Plan as a way to rise through the cult’s ranks. The one most intrigued by this twisted experiment is none other than the fourth-highest-ranking officer, Stella — a gothic lolita beauty known as “Man-Eater.”
Her desire for Oakley’s body ignites a jealous, possessive fire in Joanne, who finds herself increasingly unable to hide her feelings.
Between these two dangerously unhinged women, Oakley must soon make a decision that could unravel the last threads of his everyday life — if not his very sanity.

[From Amazon]