Vartox

He pursues the killer, Frank Sykes, to Valeron, ultimately capturing him and subjecting him to rapid aging.

This version has significantly reduced powers, apparently slightly less than the post-Crisis Superman, and a revised costume.

After a "contraceptive bomb" renders every female Valeronian sterile, Vartox comes to Earth in search of a new wife, selecting Power Girl as the prime candidate.

The two battle an Ix Negaspike, a dragon-like alien, before combining their powers to restore the Valeronians' fertility, impregnating all of them in the process.

Vartox appears in the audio drama Death From A Distant Galaxy, based on Superman #373 - #375.

Vartox from Superman vol. 1, #375, artist Gil Kane .
Vartox from Superman vol. 2, #148, artist Steve Epting .