Yuu☆Yuu☆Hakusho, Beelzebub Recommendations
Both with powerful delinquent main characters, who have to protect something; with supernatural themes of demons, ghost e.t.c.
These two are one of my favorite mangas. They may have a somewhat different plot but in the end they are very similar. Yu Yu Hakusho is about a teenage kid who doesn't really care much for most people, he also is constantly getting confronted by people who want to be beat him and become unbeatable, and goes through life dreading it, but after a life changing experience (or should I say after a life ending experience) he is swept into the world of magic and other awesome supernatural things, he meets people along the way who become good allies.
Now Beelzebub is about another
Beelzebub definitely took a bit of inspiration from Yu Yu Hakusho.
The big difference is that Beelzebub is primarily a comedy manga, and Yu Yu Hakusho is primarily a battle manga.
Both have similar delinquent characters thrust into the dealings of the demon world which are portrayed very similar in each.