Wan Shi Tong
"Humans only bother learning things to get the edge on other humans, like that Firebender who came to this place a few years ago, looking to destroy his enemy." So, who are you trying to destroy?" Wan Shi Tong is the keeper of Spirit Library, and its creator. Initially, the spirit kept his vast and comprehensive collection of all knowledge firmly in the Spirit World but eventually decided that mankind should not be denied access to such treasure. The spirit, who looks basically like a fifteen foot tall barn owl, however, believes that knowledge should be coveted only for its own sake, and not for application. Particularly, he really doesn't like it when his research in his library is used for violence, as it was when a young Admiral Zhao plundered the library's resources on both astrological events and the locations of other spirits who reside in the human world. Zhao found the mortal identities of the spirits of the moon and ocean, and then burned that section of the library to ash and made his escape from an enraged Wan Shi Tong. And so when the Aang Gang shows up in order to find something, anything, that will give them a bit of an edge over the Fire Nation, and Wan Shi Tong asks them to swear that they will not use the power of his library to hurt people... they lie. And they barely escape with their lives.