MTL - Certificate of Conformity - Chapter 126

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

Overnight, the world's common sense changed.But then...“It's common sense that erect penises are cared for with wet pussies, right?”“Customer, shall I milk it for you? Or would you like to milk it yourself?”“We promised when we were young! That I'd become your ona**le!”This is more enjoyable than I thought?Harem | Erotic | Incest

The young man named Kehma who was summoned to another world, and the useless Goddess Laura whose only strong point is having huge breasts.

Gaining a cheat skill that absorbs the abilities of what he eats, he enjoys his new adventurous life eating delicious monsters and playing with the easy to handle Goddess, all while becoming wildly overpowered/peerless in this otherworld fantasy.