Altar of the Emeralds

The Altar of the Emeralds is a place on Angel Island where the Master Emerald is kept and guarded. The earliest appearance of the altar is in Sonic & Knuckles when Sonic and Tails returned the Master Emerald to Knuckles. Although the earliest time-wise appearance of the Altar was in Sonic Adventure where both the Master and Chaos Emeralds were housed and guarded by Chaos.

Game Continuity
In the game continuity, the first guardian was Chaos. He guarded the Emeralds for an unknown (presumably long) period of time. When the Knuckles Tribe attacked the altar to fuel their expansion of conquest, Chaos was enraged and wiped out most of the tribe. He was then calmed by Tikal and was sealed away within the Master Emerald along with Tikal. The remaining echindas swore to protect the Master Emerald so that a tragedy such as this would never happen again. The last ancestor of these guardians is Knuckles, who guards the Master Emerald throughout the game series.

Archie Comic Series
See the main article, Brotherhood of Guardians.

The Brotherhood of Guardians is a fictional organization of anthropomorphic, humanoid echidnas in the Sonic the Hedgehog (Archie comic) series. They are a group of Echidnas who protect Mobius from a secret facility known as Haven and the Master Emerald. They are also Knuckles the Echidna's predecessors and family in the title of Guardian. The Brotherhood's existence is secret to all but a few individuals, including their arch-enemies, the Dark Legion.

List of Guardians

 * Edmund the Echidna
 * Steppenwolf the Echidna
 * Moonwatcher the Echidna
 * Harlan the Echidna
 * Remembrandt the Echidna
 * Aaron the Echidna
 * Jordan the Echidna
 * Mathias the Echidna
 * Hawking the Echidna
 * Tobor the Echidna
 * Moritori Rex the Echidna (Pretended to be Tobor after the real Tobor went missing and was Guardian for years)
 * Spectre the Echidna
 * Thunderhawk the Echidna
 * Sojourner the Echidna
 * Janelle-Li
 * Athair the Echidna
 * Sabre the Echidna
 * Locke the Echidna
 * Knuckles the Echidna
 * Lara-Su