Why is Nakuru Narumi so dark skinned? As we can see Nakuru Narumi has dark skin compared to other characters. So why she has dark skin tone ?
She actually does not have dark skin tone. It is fashion called Ganguro.

As MAL Describe her character as:


  The cat-eared ganguro student that is spying Konoe and Kinjirō.


Below is the defination of ganguro as described by Wikipedia. 


  Ganguro (ガングロ?) is an alternative fashion trend among young Japanese women that started in the mid-1990s, distinguished by a dark tan and contrasting make-up liberally applied by fashionistas.