Kami nomi zo Shiru Sekai II

-Both animes's setting/story goes by an omnibus format, and have small arcs that can either or not be diverging from the central plot of the story (with the setting intact) 

Within Juuden-Chan: - ditsy 'magic' girl arrives to 'make people happy' - she gets involved with a youth who sees her as nothing but a bother; he's anti-social, yet has great powers of perception - ditsy female's leads formal and apparantely more professional colegue comes into the picture Within The World God Only Knows: - ditsy 'magic' girl arrives to and recruits a boy to 'make people happy' - he sees her as nothing but a bother; he's anti-social, yet has great powers of perception - ditsy female's leads formal and apparantely more professional colegue comes into the picture 

These are really different but they have one major similarity. In Shugo Chara people create those X eggs because they can't do their dreams or something like that, while in Kami nomi zo Shiru Sekai II, people get loose souls because of something emotional inside them too. And it's up to the main characters to solve that.  

-Both animes's setting/story goes by an omnibus format, and have small arcs that can either or not be diverging from the central plot of the story (with the setting intact) 

Similarities: Both muchachos (male lead) are genius in their own right. Both muchachos wore ridiculously looking school uniforms. Both have a side kick with a rather unusual sense of loyalty to them. Both muchachos deals with women with their own unique problem and trouble also awaits them along the way . Both have school, harem and comedy genres in them. Dissimilarities: Though both animes have school genres in them, one is set in a specialize high school for geniuses while the other one is set in an ordinary high school. When it comes to school uniforms, in R-15 the girls wore beautiful looking uniforms, while the boys sport kind of uniform that makes them look like a butler. In the other anime 'Kami nomi zo Shiru Sekai" both boys and girls wore very overly decorated 60's kind of attire. One has ecchi and romance as it's extra genre, while the other has demons and magic as it's extra genre. The muchacho in one anime has a love interest, while the other maintains a lot of relationships whom are all virtual girls in his dating sims via "PFP" (or PSP for that matter). Lastly, one is a true harem, while the other is a pseudo harem.  read more 

Both anime involves dating games and making girls fall in love with the main character and those girls are spirits. They're both comedic as well. 

Cynical main characters who choose to be alone end up in a situation where they must help others whether they want to or not. There are many philosophical monologues from both as they go about their lives dealing with people and their problems. A lot of introspecting is done as they come across challenges they haven't dealt with before. 

Well it's like he's bound by Contract... and Lisara and Haqua kinda alike in some ways and they're both carrying scythe... and the protagonist both some kinda good and fanatic on their own fantasies... Also Keima and Ryouske have the same seiyuu 

Ore no Nounai Sentakushi ga... may not seem like an harem at first but later in the story, a variety of female characters start to like the male protagonist. He had to complete missions for "God" so he can get rid of his curse to be normal. The same happened in Kami nomi except that the male lead had to make the girls fall in love. Both of these anime is harem since multiple girls likes one guy and gets jealous for the things he do. 

-Both animes's setting/story goes by an omnibus format, and have small arcs for each heroine that doesn't diverge from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs for each heroine that doesn't diverge from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs for each heroine that doesn't diverge from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs for each heroine that doesn't diverge from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs that can either or not be diverging from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs that can either or not be diverging from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs for each heroine that doesn't diverge from the central plot of the story (with the setting intact) 

-Both animes's setting/story goes by an omnibus format, and have small arcs that can either or not be diverging from the central plot of the story (with the setting intact) 

They are both about bad spirits which are attracted to negative energy that need to be gotten rid of in a supernatural sense, and in both series' they reside inside people. However, Kami nomi is more light-hearted and cute, whereas Madoka is darker and a lot 'deeper' than Kami nomi.