I, Doctor in the US - Chapter 61: Psychological Makeover, "Twilight City"!

I woke up naked and all alone in a summoning circle, the only clue to my past is a demon summoning book and the hazy memories of a world very different from the one I find myself in now. I should probably be more concerned with the changes that have befallen me but I can't help but be excited to explore this new world with the new lovers I've found. After all, I'm apparently the Origin of Succubi, my actions will shape my new race in this world and all I know for sure is that I'm horny as hell.I update twice a week on Sundays and Wednesdays!Note: This novel contains a rape scene early on in chapter 8, this is not a frequent occurrence and it is not glorified or treated lightly. This is an event that affects the protagonist though so there are occasional references and allusions to the event throughout the series. The novel is loosely a genderbender but the Trans tag is for a character other than the protagonist.The series primarily features anthropomorphic characters including the protagonist which may be a turn off to some readers. The references to things like snouts and muzzles happen relatively rarely though, so you may be able to picture the characters as monster girls instead.

Logan ends up in a world of familiars, where everyone can make a contract with a familiar to get super power and grow stronger.The first familiar Logan summons is a legendary angel, and it draws a lot of shock and envy.But fate messes with him, because right when Logan is about to make a contract with the angel, the angel looks down on his plain background.“Someone as noble as me—how can I be driven by a low-born bloodline?”After that, she goes over to the noble-born school beauty, leaving the whole crowd full of sneers.Right then, Logan awakens a system, and he can see all a familiar's hidden info and evolve their bloodlines, talents, and skills without limit.“Since it won't listen, I'll switch it out, the next one will be more obedient!”With everyone laughing at him, he just made a contract with a low-level succubus.“A low-level succubus? Once this kind of familiar gets off the bed, its fighting power isn't even as good as a hyena!”“A loser with a succubus—this kid will never have to worry about women anymore, haha!”...Many years later.When demon fire lights up the stars and blood-red wings cover the sky, people finally realize—standing behind Logan are all those ancient, scary beings from myths and legends.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates