Tree of Aeons - Tree and the Snake

Invincible fists, unrivaled hammers!

Forge unparalleled mechs with the ambition of old age, and use the galaxy as a knife to smash the edge of the empire.

His name is Ji Xinghe. When he was 65 years old, he went to Alien Battlefield to avenge his son.

The old man is standing on the ground, his ambition is a thousand miles away, the old man wears armor, and fights to the galaxy, the old man drags his sword, it is not for glory.

- Description from novelbuddy

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.

Xiao Yi, an orphan raised by a disrespectful old man, possessed mysterious ancient martial arts and a unique skill in traditional Chinese medicine. At the age of twenty, he suddenly received the most baffling mission from the old man: to attend the renowned first-tier university, University Z, as a student, initiating his spectacular modern urban life. In the city, he began to write his own eternal legend...