Okay, so this one is not a manga, it's a Webtoon, but after reading this "on going " webtoon I needed to come here and share it with you. Without much delay, the webtoon is...... Noblesses.
Yes, this webtoon is amazing, and though the first set of chapters are drawn beautifully, it only gets better. Also, I should mention, the story line. Wow, unique.

here is the exert
Noblesse (노블레스) is an online webtoon written by Son Jae Ho and illustrated by Lee Gwang Su. It is a story about a powerful Noble, Cadis Etrama Di Raizel, who fell asleep for 820 years and woke up one day in South Korea in an abandoned building. With the help of his faithful servant Frankenstein, he enrolls in Ye Ran high school where he befriends Shinwoo, Ikhan, Yuna and later on Suyi. The series follows the group's often dangerous adventures against a secret organization while uncovering Rai's past. This wiki contains already 25,691 numbers of edits and in total of 706 articles since it was created in January 2011. Source (http://noblesse.wikia.com/wiki/Noblesse_Wiki)

I swear, you can't go wrong with this one, over 300 chapters and counting.