Demon King Ascension System - Chapter 8

A young middle school student faces a life-altering choice. Destined for mediocrity and without a War Spiritual Bloodline, he dreams of transcending his ordinary existence and becoming a high-status War Spiritualist. His world is transformed when he becomes bound to the “”Godly Pet Evolution System,”” enabling him to activate his War Spiritual Bloodline and cultivate divine pets, even from the most unlikely sources.Armed with this system, he defies expectations by nurturing underdog spirits into formidable allies. The seemingly weak flower spirit evolves under his care, as does his Lord White Dragon, challenging the mightiest thunder-attribute battle spirits. Even when presented with a Diamond Demonic Spirit Card, he counters with three Epic-Demon Spirit Cards of his own.His journey takes an unexpected turn as powerful entities, including the Six-Tailed Demon Fox, the Phoenix Holy Maiden, and the Queen of the Seas, vie to become his second battle spirit. Faced with a wealth of choices, he refuses to settle for just one and ambitiously aims to harness them all.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.

He has been abandoned by his clan.

He has been considered waste from his childhood but he is a “Peerless Genius”.

His father with the help of another person has sealed his Dantian to stop him exposing his exceptional talent but after his rebirth, he becomes the most dazzling star of the continent. However he faces crisis and difficulties as his Dao goes against the Heaven’s will.

Overcoming everything, eventually he achieves the highest boundary “The God of War”.

- Description from Novelupdates

In a certain world, there was someone who excelled in magic combat, people called him 『Sage』. Seeking the strongest combat art, he devoted himself to research every magic and combat arts in existence. And the conclusion he arrived at was very cruel, 『My body is not fit for magic combat』. Yet he didn’t give up. He sealed his own soul with a magic art, and was reborn in a far-off future. And the magic theory in the completely changed world he saw there was of unbelievably low level.