Currygom participated in SF short series!
http://comic.naver.com/webtoon/detail.nhn?titleId=644117&no=10
Rough summary
The main character is hearing some people telling him to choose something.
Back to past, he is talking about his fear of vast emptiness of space and how he came to rely on a god to overcome the fear.
The humanity have overcome several technological leaps and now is blooming.
The problem is that energy needed for FTL travel can be taken with only little amount from each planet.
So the main character's job is to find new planets to take resources from.
He have destroyed many underdeveloped civilizations.
But on his latest travel, the aliens have struck back with tech roughly same as 21th century humans and superhuman strength.
Also they stole the FTL drive.
Talk between non believer and main character about how no religion mentions of aliens.
Fearing they would develop their own FTL tech and strike back humanity, main character and others try to take the drive back but fails.
Everyone but main char is dead, who trusts his belief and suicides with nuclear.
And he goes to after life.
Of the aliens he extinguished.