Nebula

Han Seo grew up hearing that anything less than first place is useless.

Just as he was endlessly consumed by his own existence—unable to satisfy his father no matter how hard he tried—he encounters an extraordinary killer on his ordinary commute home.

In his haste, he kicks the man in the testicles and runs away, but the killer tracks him down to his house and introduces himself as a creature from an alien planet called 'Agape.'

Furthermore, he claims that Han Seo is a 'flowerpot' for the alien species, with a 'seed' planted inside his body...

"Do you know the easiest way to germinate a seed? It's pleasure."