Kami nomi zo Shiru Sekai: Megami-hen

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. 

- Both have the same genres; Comedy, Harem, Romance, Shounen. With the exception of Ecchi, School, and Sci-fi on To LOVE-Ru Darkness, and Supernatural on KamiNomi Megami-hen. - Both have main male lead surrounded by lots of females(well, it IS harem anime..) - Both have a really nice plot, unlike other harem anime. - There is no action genre, but both of them have some action parts. - Both anime's art is good. - Both anime's Opening Theme is good. - Both are third season, and the third season's female lead is different than the first and second season. 

They're both pretty much the serious sides of comedy anime. 

Scholar romance anime, both with love triangles although Kami Nomi develops it on the last season while WA has only one season. The endings are different in the original sources since the story continues, but in terms of the series adaptation both have the "bad" or sad ending.  

Have similar plot settings (date simulation) have in common conquer girls by kissing Taking school plot. 

Both main characters have a love for games which is responsible for them meeting a girl they fall in love with.  

What it truly represents on how the anime will progress... Gets a bittersweet yet scenes that torn apart and also she's one of the member who make a light music club of course band Chihiro = Fuuka 

Both play on Greek Mythology by names and Male MC conquers girls for his harem by kissing. 

The World God Only Knows III and OreImo 2nd Season Specials (the final ending) deliver some of the most unconventional wedding scenes ever happened involving main characters. This left me wondering about my future. Are all otaku weddings bizarre to this extent? 

I'm a bit surprised no one ever mentioned this. Both shares a rather similar harem chemistry: The male lead is trying to form a harem route. Both also falls within comedy romance but Seitokai no Ichizon is leaned towards comedy portion more while Kaminomi zo Shiru Sekai take things a bit more seriously. 

Both are representations of a genius strategist who risks it all to conquer while trying to save the ones they love, and the downfall of their own humanity in the process. While they are wildly different in context, Keima and Lelouch have a surprising amount in common--and, while Code Geass R2 is certainly much more serious and adult, The World God Only Knows S3 is shockingly mature and raw for a harem show even with its comedic context. Highly recommend both shows!