One Piece: Supreme Check-In System - Chapter 56: Void King and Surgeon

Aaron, a wildlife biologist, became a military strategist right after a global war between nations began.He never wanted to participate in the war but he had to, because he wanted to continue his studies on endangered species the moment the war was over, but to his surprise, everyone in his unit were killed, including him, and the next thing he knew, Aaron woke up in the body of a young noble having a similar name to his.However, he also noticed he had awoken in a world different from Earth.In this world, demonic beasts ran rampart with only one thought in mind, causing them to feed on anyone they see, be it humans, elves or even magical beasts as well.During his first encounter with a magical beast, Aaron awakened a system which allowed him to bond with magical beasts and to obtain terrifying abilities from these bloodcurdling magical beasts, so he used his experience as a wildlife biologist to help make it easier for him to bond with these beasts.However, Aaron also noticed he could evolve these beasts if their loyalty towards him had reached a certain level, so he vowed in his heart to grow strong enough to protect those he cared about in this world with the hope of living a happy, peaceful life where he'll be able to focus fully on his passion as a wildlife biologist.

After the ‘100-Year War’ between the Necromancers and Priests, an all-time genius who’ll shake the power structure was born. “Am I a rare case or something? Do I have talent?” A potential beyond all imagination. He obtained his father’s undead army and entered the great Necromancer school of Kizen that divided the continent. Geniuses are geniuses, even when gathered among the elites. The research community was flipped on its head by the appearance of a new case. Professors wouldn’t leave him be alone, wanting to make him study directly under them. Officials from all over the kingdom and heads of organizations fidgeted over whether to scout him. “Professor! When can I make a Lich?” “Gimme a break. How talented are you? You’re crossing the line, honestly.” A genius among geniuses had appeared.

I was a good looking prince when I was reborn, and because I could do indecent things as much as I like, I decided to make a harem while traveling with a beautiful female elf~

Shi Qing Xia is practically an angel.

Kind, sweet-hearted, and good at her studies, she was admitted to the top university in Taipei.

However, the living expenses for the metropolitan city were far greater than she had ever imagined, so she started to work as a private tutor for wealthy families to make ends meet.

On her first day of work, she met Zhao Yi Bo and Zhao Yi Xuan, a pair of neglected 16-year-old genius twins whose prosperous and wealthy parents heartlessly abandoned in Taiwan. Shi Qing Xia found them to be gentle, compassionate, friendly, clever, mysterious, pitiful and attractive.

But appearances can be very deceiving…

Because behind those sweet smiles…

Deeply twisted and cruel demons lurked, waiting to rip apart the wings of this angel, condemning her to an eternity of conflicted bittersweet suffering — a rollercoaster ride of a heart-wrenching, twisted, and tragic romance more extreme than what someone so innocent could possibly imagine.

- Description from Novelupdates