Description I'd been killing slimes for 300 years-and then I had to go into a huge dungeon I didn't really want to go at first, but after exploring it, I finally discovered that the exciting life of an adventurer...is probably still not for me. (Maybe a little?) Then there was that visit to Beelzebub's house and sending my daughters to school-things have gotten so busy I've almost forgotten how to take it slow About the Author Benio is the illustrator of I've Been Killing Slimes for 300 Years . Kisetsu Morita is the author of I've Been Killing Slimes for 300 Years .