I am looking for an old manga about spaceship battles, the story was, if I remember correctly, about a soldier in the spaceship, eventually climbed up the ladder to the end of the story where he became like a king of the space, killed off his enemy's entire families, and married the 2nd girl because the main female character died somehow ... I only mostly remember the ending ...

Ginga Eiyuu Densetsu or one of its adaptations, maybe?