Multicrossover: I Took Utaha's Virginity At The Beginning! - Chapter 54 - 53: Victory is Mine

A part-time job contract. He became the cold CEO’s imitation boyfriend. He merely wanted to earn a few small bucks and live a comfortable life, but a pity, he was in constant turmoil since then. Well, life had something else for him despite his wishes.“That… beauty, will there be an increase in wages for conversion from ‘boyfriend’ to ‘husband’?”

- Description from Novelupdates

Ethan transmigrated from earth to a post apocalyptic martial world with a system.His system has only one function: Double the attribute every day. Watch him rising in the universe with a pace faster than the speed of light.

Lenny, an orphan from the Sector 41 slums, suddenly finds himself in possession of a rare and unknown affinity. It allows him to upgrade himself, using energy acquired from spirit beasts. But will he gain enough power to defend himself against those with every advantage he has never known?Explore the Western Alliance, where the Four Pillars rule supreme, and all vie for the title of the strongest faction. But when those sworn to protect the people fight amongst themselves, who will save them from the biggest threat they've ever known? And can one young boy, with no family and a handful of friends, survive all that chaos?

Entering Tokyo in the bubble era, in this strange era, the only familiar ones are Matsuda Seiko, Nakamori Akina, Kudo Shizuka…

- Description from novelbuddy