Info from WIKI
Three was a very sadistic monster who seems to enjoy toying with his victims before killing them. He even goes as far pretending to fall asleep in front of his enemy. His hatred for humans, likely came from the fact that he viewed them as hypocrites, since they, too, kill anybody that's different from them. Despite his arrogance, he was shown to be very cowardly when dealing with an actual threat, like Zero or the shotgun. His teammates called him a coward as well.