Natsume Yuujinchou San

Both main characters can see weird creatures, same mystery, and similar plots. Each episode new story new characters.  

youkai~~ Natsume is refreshing relaxing and this one is filled with combat but somehow i feel like they same 

Not only do Natsume Yuujinchou and Hotarubi no Mori e have the same original creator and similar setting, they are animated by the same studio, with the same director and even the composer is the same. Without any doubt there is more than one that these two would both be liked by the same people. The girl, Hotaru, in Hotarubi no More e and the boy, Takashi (mostly referred to by his family name Natsume), both see demon and spirits and they both befriend them. Both the film and the series play with a melancholic feeling and the relationship between humans and spirits. 

Both of these animes are about the world of youkai and a boy trying to hide them from his friends. Otheer than that the plot are different but their both amazing 

Similar theme with spirits and building relationships over time. 

The stories maybe very different, one is about romance while the other is about supernatural. But both animes give a very similar feeling-warming and touching. The 2 main characters, Natsume and Sawako are very lonely at first and later make friends that changed their life. 

-Both anime's moods, animation, and flow of the story/plot are very lighthearted. -Both are slow-paced and centered around Slice of Life over Comedy. -Both have the calming quality. 

Supernatural incidents and creatures exist & the main character can see those creatures in both animes. Characters are more diverse, interesting and funny in xxxHolic. Natsume Yuujinchou is a bit more slowly paced anime. 

The atmosphere and calming nature of the story and pacing is practically identical between the two. While Aria does not deal much with spirits, it does deal extensively with human nature and understanding/remembering the finer things in life.