Global Reincarnation: Only I Know the Plot - Chapter 13:

Let her shout out: “Oh handsome and sweet-talking Tokyo gentleman, I must have you. You are mine!”This is the story of how a boy from Iwate Prefecture became a Tokyo gentleman.

Good and bad luck has followed Zach ever since he was five. Poor guy. His life has been far from the sweet and peaceful paradise one might expect of the youngest son of one of only four dukes in a great Empire.But a little more excitement than expected doesn't stop him from pursuing his dreams of summoning, and perhaps his luck is finally turning once he manages to summon something great.Armed with maids, a scummy gift of luck, and a strong will, Zach sets out to live life as he pleases, even to the annoyance of those around him. First stop: The Academy.

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

After dying from betrayal, Thomas reincarnates as Jolthar Kaelzhar, the neglected son of a powerful clan, just after his brothers kill him. With Jolthar's memories and the blessing of Qalena, Thomas vows to rise from his lowly position and claim power in his new life.