The most famous yōkai are Tengu, Oni (Japanese ogre), and Kyubi no Kitsune (a fox with nine tails). When some people and animals are filled with hate, they became yōkai. For example, Sutoku. Sutoku (Japanese ancient emperor) died filled with hate. Then, he became a Tengu and caused a disaster. Also, a cat which lived too long time became Nekomata.