Anime about a girl found by the lead character in the ruins in the sky who attracted a monster to a village inhabited by spirits I stumbled across a really interesting anime which starts out with two young men exploring the ruins floating in the sky, looking for relics of the ancient heroes. They stumbled across a girl who passed out and, when she woke up, refused to tell them who she was.

They brought her back to the village, only to be explained that she couldn't see the lead character's friend or any of the villagers as they were "spirits", and the lead character was only able to see them because, having grown up there, he has become accustomed to their "presence".

The girl ended up attracting a monster, which broke through the barrier protecting the village, forcing the villagers to defend themselves.

That's as much as I can remember, unfortunately. Hopefully this is enough information.
Sounds like Tales of Zestiria: Doushi no Yoake.

It had an OVA produced by Ufotable and aired last December 2014 in order to promote the original game.


  The story focuses on Sorey who goes on a quest to restore peace on their homeland. The woman you might be referring to is Alisha, the brown-haired girl from the picture, whom Sorey, the dark brown-haired guy, and Mikleo, the white-haired one, met when they were exploring these said ruins. They brought her to Sorey's land, which was inhabited by these spirits, where only Sorey could actually see them. 


Source: Wikipedia