MTL - Strong Waist - Chapter 402 Let'sgoArsenal！

Amakawa Haruto died before he’d the chance to reunite with his childhood friend who disappeared five years ago. Rio, a young boy living in the slums seeks revenge for his mother who was murdered in cold blood in front of him when he was only five years of age.

There exists the earth many knows of and there exists an alternate world. Two people, each with their own backgrounds and values. For odd reasons, the memories and personality of Haruto, one who should have died resurrects in Rio’s body. As the two are confused over their memories and personality fusing together, Rio (Haruto) decides to live in this new world.

Along with Haruto’s memories, Rio awakens an unknown but special power. If he’s to use it, it looks as if he can live a better life, but before that, Rio encountered a kidnapping which results in involving the two princesses of the Bertam Kingdom.

After saving the princesses, Rio is given a scholarship to attend the Royal Academy, a school for the rich and powerful. His background being a poor orphan who once lived in the slums, the school full of nobles was rather a detestable place to stay at.

A Di [legitimate-born] daughter of a noble house turns into an abandoned daughter. No father to dote on her, no mother to love her, no problem. She uses one silver needle to save a dying man. What’s so unusual about a medical injection? She roams all over the world with a scalpel in her hand. Cutting throats, cutting open abdomens, cutting open skulls to mend bones. With amazing medical skills and ethics, she gathers a flock of officials, obtains the will of heavens, gains public favor, and receives Taizi’s [Crown Prince] doting. In the midst of a powerful momentum, her cheap father comes to reunite. She coldly refuses to go home or acknowledge ancestors.

“I was abandoned by you over and over again. Now you want to use familial affection to coax me back. You don’t want to recognize this daughter. My heart is cold, I want to leave. Beat it, father!”

- Description from Novelupdates

Died while saving his dear friend and cursing the arrogant general, Leo gets reincarnated into a world ravaged by magical beasts.Here, strength speaks for everything, and the weak are killed at the whims of the strong. Leo awakens as the lowest-tier Beast Master. Just as he was thinking he would again end up under the command of some stupid general who was the reason for his death last time, he received a gift from a mysterious entity.[Primordial Beast Dominion system]Now, surrounded by people who see him as a weakling, his journey to grow the strongest has begun.Where everyone is beating their head to make their beast grow and unlock their potential, Leo uses the system to break his limiter and grow fast and surprisingly strong.With dual talent, a broken system and a yandere sister, he embarks on the journey to rise at the top of the food chain.