This Immortal

Roger Zelazny

1966

Dystopias > Fiction.
Imaginary wars and battles > Fiction.
Human-alien encounters > Fiction.

"...and call me Conrad!" Such was the only comment that Conrad Nimikos would make on his life-history, an enigma that faded out in lost records and obscurity a few decades back. There were those who said he had since had a different name, that of the liberator of Earth, the man who had fought the star-empire of Vega to a standoff. And some even said that he had had other names, stretching back through centuries...But Conrad wouldn't talk about his past. For the future was at stake now-the future of Earth and her peoples, as the Vegans returned on a mission which would decide for all time the place of Earth among the worlds of the stars.

Ace Books

https://catalog.hathitrust.org/Record/102699421

English

Aliens