Belleros was a resident of Corinth who was killed by Bellerophon.
Percy Jackson's Greek Heroes[]
When Bellerophon, then known as Hipponous, was throwing knives at bales of hay with his friends, he said hello to the prince who turned towards him to reply, unintentionally threw his knife at him, killing him and having the prince branded with the name “Bellerophon“, meaning “killer of Belleros”.