MTL - The Rest, Only Noise - Chapter 6 Athens, USA? probably

Inexplicably reborn in the year 2003, having failed terribly in his previous life, the prevailing concern with Xu Tingsheng, that stands above all else, is none other than her. But alas, he is just months away from entering university, while she is but in her first year of junior high… Regarding this, all he can do is wait silently…for now.

Noda Sagiri is the only girl in her karate club, she has little feminine attributes but has a hidden talent in making sweets. On a whim she decided to bring her handmade cookies to her club, but after one of the idols of the school Michel François tasted her cookie he suddenly declared “I must meet with the girl who made these cookies!”. The search for the cookie maker began, however it seems that no one would come to expect that Sagiri is the one who made them….

[You have become the master of the Warden Mansion.][Your first quest is to refine mana from one of your maids by having intercourse with her.]When nineteen-year-old Jett Talon suddenly wakes on an emperor-sized bed, he finds himself lord of a mysterious mansion where countless gorgeous maids stand ready to serve. His first companion is Mia, a blonde elven maid who checks his every box. After making love to her, Jett gains mana, unlocks legendary powers, learns his duties as Master of the Warden Mansion, and uncovers its hidden secrets.

The eldest son of the assassin aristocrat Tuatha Dé.

The skill, experience, knowledge of the previous life, magic, all of which grows his power as an assassin.

Excellent assassins pass through. He was usually admired as the ideal lord, and behind it wielded a blade as an assassin aristocrat.