 If you liked
Beelzebub
|
 ...then you might like
Princess Lucia
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Demons attaching themselves to humans is the common theme, although one is a shonen battle manga and one is a harem manga.
Similarities include demons forcing themselves onto the protagonist, high school life, supernatural phonemon, and crazy magical battles. Although the plots differ the feel is very similar. In Princess Lucia, Lucia forces herself onto Yuta (the protagonist) wanting to make a baby that will be able to take over the world. And in Beelzebub Oga has baby Beel shoved on him so that he can raise him to destroy humanity/world. Both are funny and while P.L. focuses more on relationships and less on conflict than Beelzebub but are deffinately worth the read.