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You won't be able to survive in your reincarnation unless you have sex with mob demons!

"Thank God it's me for the first time." If you lick and suck both inside and out like that... your magical power will overflow!
I'm not sure what to expect, but I'm sure I'm going to have a great time! This demon...he's too good at sex even though he's a mob and a non-aggressive character!
--Mia, who died from overwork due to hard work, was reincarnated as a saint heroine in a "bad-ending, 18-rated, forbidden otome game. If she doesn't do anything, she will enter the demon brothers' hard sex route and die again...
So, Mia decides to use the heroine's vast magical power to raise the youngest mob demon, Caius, as her bodyguard!
However, the only way to transfer the magic power... is through extremely pleasurable sex!
Caius is a demon who can't stop pistoning in all kinds of places... in all kinds of positions... even if he comes and comes and comes!
Caius, who is trying to overtake his older brothers, devours Mia's body with his bottomless vigor...
The flags of love and the appearance of the older brothers appear one after another.
What is the fate of Mia who wants peace and quiet?

English Webtoon version: https://comiko.net/series/132780/tensei-saki-de-wa-mob-akuma-to-sex-shinai-to-ikinokoremasen-official