Athair is a fictional character from the fictional universes of the comic books and TV series based on the Sonic the Hedgehog series of video games. He is the great-grandfather of Knuckles the Echidna, and as such is an anthropomorphic, humanoid echidna. In the comic universe he has brown fur; the cartoon in which he appeared depicted him with red. His eyes are blue in the comics, while they're black in the cartoon.
In the Archie-published Sonic the Hedgehog comics, Athair has had two wardrobes. One is a somewhat tattered tribal outfit, complete with a walking stick; the other is a plain white robe. In either form of attire, he wears the spiked mittens of the Guardian family and a pair of sandals. His only other decoration are the beads that have been looped over his dreadlocks. Following his assumption of the white robe, he appears to Sonic and co. in the form of a disembodied floating head.
In the cartoon series Sonic Underground, in which he was voiced by Maurice LaMarche, Athair is dressed in a white and blue robe, and also carries a staff, far more regal that his usual walking stick. He also wears a green-lensed pair of glasses.
Athair's name is translated as 'Father' in the Irish language (pronounced 'a-HAR'), and Athair is the only Guardian besides Knuckles to appear on television.
Athair is the son of Janelle-Li, the only female Guardian (currently) in the history of the Brotherhood of Guardians. Athair followed the usual Guardian tradition of assuming the position around 8 or 9 years old, but then was taken by the Ancient Walkers to Haven, where his mother surmised that he had a different destiny. Athair resigned his position, and began learning from the Ancient Walkers. In addition, he became leader of the Lost Tribe of Echidnas as they sought their homeland of Albion. When his mother died, he was expected to reclaim the position, but he refused. His son Sabre, furious at him, took up the position at age 7. Worse for Athair, his wife Crystal-La was later captured and Roboticized.
His first encounter with the Freedom Fighters was during time he spent in Downunda. While living in this desert, he took up residence in the Great Crater, once resting place of Angel Island, and became known among denizens of the continent as "Ol' Weirdo" due to his reclusive nature. During his stay, the Downunda Freedom Fighters brought him a guest: the then unconscious Miles "Tails" Prower. Nursing the Fox back to health, Athair told Tails stories of Mobius' past and revealed the young Freedom Fighter's destiny as the Chosen One. Athair afterwards disappeared, leaving no trace behind.
Following Mammoth Mogul's success in draining the powers of Enerjak, Athair reappeared to aid the beleaguered opposition, which consisted of Tails, Sonic, and Knuckles in their Super forms; the Freedom Fighters and the Chaotix; the Brotherhood; and a number of other groups opposed to Mogul's takeover. Delivering the Chaos Syphon to his beleaguered allies, he watched as they overcame Master Mogul-only to vanish yet again. Shortly afterward, Athair returned to recruit Knuckles, bestowing upon him duties as Mitre of the Lost Tribe of Echidnas. He disappeared again, leaving the tribe in the capable hands of Knuckles and his allies Rob O'The Hedge and Mari-An. The trio soon reached Albion with the tribe, and while Rob and Mari-An remained near Albion to protect its entrance-getting married at the same time-Knuckles departed for Angel Island. As he left, the faces of Athair and the Ancient Walkers appeared in the clouds above him, smiling down in approval.
Athair later returned, apparently having taken up residence in the same dimension as Aurora. He appeared to Tails yet again, appearing only as his disembodied head. In this form, he assisted Tails in his rematch with Mammoth Mogul, giving Tails the knowledge necessary to combine with his numerous alternate selves to form Titan Tails. Later, as the Ancient Walkers felt themselves dying, Athair was chosen as one of their successors; the others were Aurora and Merlin Prower. Unfortunately, Athair's new role was forced upon him all too soon, as the Arachne used the Sword of Acorns to release Ixis Naugus, producing a dimensional warp that finished off the Ancient Walkers. Elias Acorn later revealed that Athair and his compatriots are known as the Neo Walkers.
In Sonic Underground, Athair appears as a wiseman and seer, foretelling doom if Knuckles leaves the Floating Island. He helps Knuckles and co. by providing them with a canister to contain a broken Chaos Emerald, the energies of which threaten to destroy the planet. However, Sonic, Sonia, and Manic are reluctant to heed his advice when he claims that they must form an alliance with Dr. Robotnik to save Mobius.
As one of the Guardians, Athair has a variety of abilities stemming from his connection to the Master Emerald. In addition, he possesses a variety of other powers, most likely taught to him by the Ancient Walkers. In addition, Athair can exist both on mortal and on omnipotent planes of existence.
The Athair of the comics is a light-hearted individual, having long been freed from the responsibilities that have darkened the dispositions of so many of his family. However, he does have the horrors of his own past weighing on his mind. Sarcastic and prone to humor, Athair is given to talking in riddles, which confuse Sonic and Tails to no end and are often frustrating to Knuckles as well. Despite their occasional arguments, he and Knuckles do share a number of things, which eventually includes the idea that Angel Island's safety is no more important than the safety of Mobius at large.
Sonic Underground Athair is more serious, and brooks no argument when he makes a decision. However, he is shown to possess some of his comic counterpart's humor, and clearly thinks well of his great-grandson.