Athair was an Echidna that transcended his corporeal form and became an emissary of the Ancient Walkers. Athair was the first Guardian to abandon his position and pursue a "higher calling". Guided by the Ancient Walkers, Athair became the Mitre of the Lost Tribe and spent many years leading them in their search for Albion, until his great-grandson Knuckles completed this task. Athair also spent some time in his later life training Miles "Tails" Prower for his role of becoming the Chosen One and continued to do so even after his transition into a non-corporeal entity. After Tails fulfilled the prophecy and stopped Mammoth Mogul, Athair remained with the Ancient Walkers. Following their demise, Athair became one of the Neo Walkers.
Athair was born the son of Janelle-Li, the only female Guardian in the history of the Brotherhood of Guardians. His father Nemo died when he was an infant, leaving Janelle-Li to raise him alone. At some point Athair had even been to Echidnaopolis as a child. Athair followed the usual Guardian tradition of assuming the position around 8 or 9 years of age, at which time his mother left him on his own to join the Brotherhood in Haven. However, not long after his time as the island Guardian began, the Ancient Walkers appeared before him and informed the young echidna he had a higher purpose. After transporting him to witness the Lost Tribe of Echidnas, he was taken by the Walkers to Haven where he encountered his mother. Despite his objections, Janelle-Li took up Athair's position of Guardian for him, as she too sensed he had a higher calling. From there, Athair began learning from the Ancient Walkers, and became the Mitre of the Lost Tribe as they sought out Albion. (KtE: #11, CSE)
Years later while leading the Lost Tribe, Athair was struck by the Soultouch when he met Crystal-La, and the two eventually married. One season later his son Sabre was born. After seven years, the Ancient Walkers appeared before Athair and explained his mother was terminally ill. Sabre urged Athair to tend to his mother and resume the mantle of Guardian, but Athair refused, deciding to remain with the Lost Tribe. His son, furious at him, took up the position at age 7. Worse for Athair, his wife Crystal-La was later captured by the forces of Dr. Ivo Robotnik and roboticized, along with many other members of the Lost Tribe. (KtE: #11)
His first encounter with the Knothole 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. Shortly afterwards Athair was presumed to have died when Crocbot's escape vehicle crashed into the crater and caused a massive explosion. Instead, Athair merely shed his corporeal form. (TMS: #2, #3)
Athair encountered his great-grandson for the first time when Knuckles began on his quest to find the Sword of Acorns. Their first meeting began with immidiate hostility from Knuckles, who criticized Athair for not being brave enough to assume the mantle of Guardian. Athair retorted "Who are you to judge? Wisdom decrees that it is better to safeguard a universe than just one pebble in its belly!" When Tails began to explain why they had sought him out, Athair cut him off and told him he already knew the reason, after which he transported both Knuckles and Tails to see the Ancient Walkers. (StH: #42)
When the Dark Legion managed to escape from the Twilight Zone and began invading the Floating Island, Athair appeared before Locke in Haven and gave him an ambiguous warning of things to come. (KtE: #2)
After Mammoth Mogul successfully drained the powers of Enerjak and banished Sonic, Tails and Knuckles to an alternate zone, Athair appeared before the three heroes and provided them with an escape route back to Mobius Prime. When they engaged Mogul in combat, Athair enabled their transformation into their super forms without actual Chaos Emeralds, giving them with a chance to defeat Master Mogul. When even their super forms seemed inefficient to overcome Mogul, Athair provided a Chaos Syphon to Turbo Tails, enabling him to drain Mogul of his power and defeat him. (StH: #56, KtE: #9)
Shortly afterward, Athair travelled to Echidnaopolis to recruit Knuckles as the last Mitre of the Lost Tribe. After transporting himself and Knuckles to the location of the tribe, he explained the history of the Lost Tribe to Knuckles. Later that day Athair sensed that the most recent Day of Fury was about to begin. As the ground opened up the tribe nearly fell victim to an emerging flow of lava. However, Athair used his powers to lift the members of the tribe into the air, bringing them out of harms way. Later that night Athair explained to Knuckles his childhood and why he chose to abandon his position as Guardian in favour of leading the Lost Tribe. After Knuckles went to bed, Athair told to Yanar that it would be the last time they would see one another as he had a "higher path to follow". He disappeared again, leaving the tribe in the capable hands of Knuckles, who managed to successfully lead the tribe to Albion with assistance from Rob O' the Hedge and Yanar. As Knuckles left the city Athair and the Ancient Walkers appeared in the clouds above, smiling down in approval. (KtE: #10, #11, #12)
Following the Dark Legion's attack on Angel Island with the Quantum Beam, Athair appeared before Knuckles, who managed to jump off the island before being sent to an alternate zone. Athair explained that the answers Knuckles sought could be found in Albion, and that he would need a guide in the form of Rob O' the Hedge. Before vanishing, Athair reminded Knuckles he already had the means to get to Albion. (StH: #88)
The next time he showed up, Athair appeared in Knothole High School before Tails, telling him he was needed. After he transported Tails to where Chaos Knuckles was located, he explained that Knuckles was evolving. Shielding Tails from one of Chaos Knuckles' blasts as the echidna teleported away, Athair then transported Tails to the Floating Island where Chaos Knuckles teleported himself to. After Tails was injured in an attack, Athair teleported him to Merlin Prower. Athair informed Merlin that the Ancient Walkers were dying, and that Turbo Tails needed to be summoned to combat Chaos Knuckles, otherwise entire worlds would be destroyed. Explaining the agony his great-grandson was suffering through, Athair convinced Merlin to summon Turbo Tails. After Chaos Knuckles quickly defeated Turbo Tails, Athair probed Tails' mind and discovered that this was a duplicate, the location of the real Tails unknown. Athair explained they should not inform the false Tails of this without knowing how the switch occurred or who was responsible, transporting the duplicate Tails to Knothole. (StH: #94, #95, #96, #97)
Athair later returned, apparently having taken up residence in the same dimension as Aurora. Following Knuckles' death and his brief merging with the Chaos Force, Athair asked Aurora why she didn't inform Knuckles he was worth of a second chance at life. Later when Knuckles returned, having rejected being merged with the Chaos Force upon sensing the Xorda threat to Mobius, Athair confirmed to Knuckles he could have a second chance, but warned him the result of returning would have unknown consequences. After Knuckles returned back to life, Athair explained to Aurora Knuckles' young age played a key part in his reasons for rejecting being one with the Chaos Force. (StH: #124, #125)
Some time later, Athair appeared to Tails again, appearing only as his disembodied head, explaining how Mogul had replaced him with a doppelganger and usurped power from the real Tails. Tails pressed Athair to tell him the full truth about the "Chosen One", but Athair simply vanished. After disappearing, Athair's voice told Tails to be patient, stating that the hour of the Chosen One would soon be at hand. Not long afterwards, Athair helped give Tails the knowledge necessary to combine with his numerous alternate selves to form Titan Tails in order to combat Master Mogul, who had been reshaping the multiverse. After Mogul was defeated and Tails used all his power to undo everything Mogul had done, Athair and Merlin conversed about Tails' decision to return things to normal, leaving Mogul's imprisonment in a Chaos Emerald the only evidence of the battle. (StH: #148, #149, #150)
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. When Merlin left New Mobotropolis to continue his training to become a full Neo Walker, Athair became his mentor, having already ascended to that state. (StH: #162, #163, #164, #187, CSE)
Athair is at times 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, and takes seriously the burden of watching over Mobius. 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. And oddly enough, him and his grandson aren't exactly close as the two rarely speak and when they do, they usually argue. Athair is usually reasonable, but can be harsh and unyielding when strained.
Athair typically appears as an old echidna with brown fur, often carrying a gnarled walking stick. He wears what appears to be a fuzzy tan covering of sorts with simple brown sandals and white gloves (notably lacking spikes like most Guardians). He wears a necklace with two gourd-like objects and his long dreadlocks are adorned with large beads in greens, yellows, oranges and reds. The length of the dreadlocks as well as the size and number of beads often varies between artists. Some depict him with whiskers.
Drawn as a child, his attire was the same; the only difference was the lack of age and wrinkles. Within the Chaos Force he was seen wearing a flowing white robe and sandals.
As a trained Guardian and an acolyte of the Ancient Walkers, Athair has developed a strong connection with the Chaos Force that grants him many abilities. While he rarely displays most of his talents, he has shown a great proficiency for teleportation and telekinesis, traits often exhibited by other Guardians. Upon ascending to the Virtual Zone, his abilities increased dramatically, to the point where he became able to astral project himself-usually in the form of a disembodied head-to other locations and communicate with other mystically inclined beings.
- Athair was the only member of Knuckles' family to appear on a Sonic TV show, and in any media outside the comic series; he was featured in the saga "Chaos Emerald Crisis" of Sonic Underground. Athair is also the first instance of any Sega character being given a great-grandparent character, and with his wife Crystal-La is one of only two such characters to date.
- Apart from Edmund (P.X.E.), Athair is the only comic-exclusive Guardian not to have been created by Ken Penders, but rather by Michael Gallagher, who created most of the characters introduced in the Tails Miniseries, in which Athair made his debut.
- Athair's name comes from the Old Irish term athair, meaning "father". Perhaps as a play on this, the Athair featured in Sonic Underground spoke with an Irish/Scottish-esque accent, which has been compared to that of actor Sean Connery, though he was played by actor Maurice LaMarche.
- Due to living in the Virtual Zone as a Neo Walker, Athair is one of a handful of Echidnas who has not either been imprisoned in the Twilight Cage or be banished by Thrash the Devil from Albion. Apart from Knuckles, he is also the only Guardian-current or former-not to have been imprisoned in the Twilight Cage. However, given the recent alterations to Mobius' reality, his status is now in question.
- In Sonic Underground, Athair was redesigned in the series and was voiced by Maurice LaMarche in the style of Sean Connery.