Well I'm surprised that he nor his brother have been mentioned yet, but Simon:
Anime: Tenga Toppa Gurren Lagann
Power: He is the greatest source of spiral energy in the universe, thus the closest to producing the spiral nemesis.
Became God: He gained the powers when he found the Core Drill and Lagann but was did not obtain godly powers until after he defeated Lord Genome.
I would say Kamina but no matter how manly he is his powers were not quite that of a god. Maybe a god of manlyness?
And because it needs to be said, Muto Kazuki a.k.a. Victor III:
Anime: Busou Renkin
Power: When in Victor III form he can use Energy drain, which is able to drain all the life force from any living thing within a certain radius. Also uses Sunlight Heart, a lance formed from his kakugane.
Became God: When the black kakugane in his chest activated his victorization.
When by pure existence you kill all those around you you really need to be considered a god.