Ajin - dark but good.
Hero Waltz - short, you can read it in 1 day.
Legend of the Sun Knight - if the art style doesn't bother you, it's actually a comedic masterpiece
Trace - obligatory mention.
Akatsuki no Yona - says shoujo, but it's not extreme, give it a shot if you have the time
And from the mentioned above, Holyland, Ruler of the Land and Kubera are hands down my favourite, you should give them all a read if you haven't already.
- Mr. Mailman and clamzoopa like this