Kami nomi zo Shiru Sekai

Kama Katsuragi is some geek that spends all day being anti-social playing. Until one day he signs a contract with a demon from hell called Elise to capture all of the hidden blue soals. By doing so he needs to make a target specially a female character fall in love with him.

I really liked this series overall, sure it can be a bit nerdy at times and melodramatic but still enjoyable.

It has some good character, some cute girls who could cause a waifu war. (Personmally Chihiro or Ayumi are my favourite girls)

The dub is good too.

So yeah do check this out.