Tensei Shitara Slime Datta Ken

That Time I Got Reincarnated as a Slime (Japanese: 転生したらスライムだった件 Hepburn: Tensei Shitara Suraimu Datta Ken) is a Japanese fantasy light novel series written by Fuse, and illustrated by Mitz Vah. It was serialized online between 2013 and 2016

Satoru Mikami, an average 37 year old office worker from Tokyo with no girlfriend, was asked for marriage advice by his colleague Tamura. After meeting him and his partner Miho on the street, he is stabbed to death by a passing robber. After making some requests during his death, he is reincarnated in another world as a slime with the ability known as predator (which can devour other creatures and obtain their abilities). Upon making friends with the dragon Veldora, the slime, now known as Rimuru Tempest, embarks on a journey to find a way to free Veldora from his seal, encountering many different races along the way (along with embarking on side quests throughout the story)