City of Sin - Book 1, Chapter 23B

Join Lu Yin on an epic journey across the Universe, pursuing the truth and tragedy of his past. This is a world of science fantasy where the older generations step back and allow the young to take charge of affairs. Heart-wrenching separations, terrifying situations, all with comic relief that will leave you coming back for more. This is a world where the other characters actually matter, and are revisited frequently as their own lives unfold. Dotting Lu Yin’s path are monumental feats of kingdom-building and treacherous political situations where he must tread carefully if he wants to get to the truth of his history.

By accident, Lu Zhiyu found the entrance to a low-dimensional world, and thus began a totally different journey!

Xiao Yu, who was a student from modern Earth, accidentally transports to another world and becomes the lord of a territory. Facing an unfavorable situation, he vows to take back his family business, build his new territory, kill all of those who covet his wealth, and dominate the world!

- Description from Novelupdates

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