Only in ecchi manga are demon lords sexy.
Also known as There’s a Demon Lord on the Floor, the first 4 volumes of this manga start out with nothing but tease. The art is consistently fantastic and detailed but ecchi content can become a little trite. However, volumes 5 and 6 shatter the nipple barrier, and because the art’s so awesome the payoff is amazing.
Sadly those last two volumes (and volume 4) aren’t the greatest quality. I managed to get my hands onto digital copies for the first three volumes, but unfortunately that wasn’t the case with the other three. I might do a remake of the last three volumes when there are better scans.
Floor ni Maou ga Imasu (6 Volumes, Ongoing)