Danganronpa: Kibou no Gakuen to Zetsubou no Koukousei - The Animation

A group of 15 elite students is gathered in a very special high school. The school is under the direction of a bear called Monokuma, who explains to them that their graduation revolves around murders. The only way to graduate is to kill one of their classmates without being discovered. If the others discover the killer's identity, the assassin is the only one to be executed. However, if they fail to catch the killer, only the assassin graduates and the others are annihilated.