Knuckles the Echidna is a character from Sega's Sonic the Hedgehog series. He is a red anthropomorphic short-beaked echidna who is Sonic's secondary best friend and former rival. Determined and serious, but sometimes gullible, he fights his enemies using brute force and strength. His role is established as the guardian of the Master Emerald, a large gemstone which controls the series' integral Chaos Emeralds, and is the last living member of his tribe, the Knuckles Clan.