O'Nux

Anti-Knuckles is a Mobian Echidna and Knuckles' alternate self from the dimension of Moebius.

Coming to Mobius Prime
Having lived on and defended the Sunken Island for his entire life, Anti-Knuckles' only known moment of tension came at the same time he met his Mobius Prime counterpart. Tricked by Evil Sonic into helping him steal the Chaos Emerald from Mobius Prime's Floating Island in order to save his own home, Anti-Knuckles was actually persuaded to do battle with Knuckles on Mobius Prime and then on Anti-Mobius. So great was his belief that violence was wrong that Anti-Knuckles wasn't even willing to harm another to save his home and all its inhabitants.

Despite this, he joined the Knothole Freedom Fighters as they investigated the deterioration of the Sunken Island's giant air bubble, and discovered that it was the work of none other than Robotnik Prime, who was looking once again to obtain power through Chaos Emeralds, this time from Anti-Mobius. With Evil Sonic defeated and Robotnik nearing success in his plan, Anti-Knuckles joined forces with his counterpart, using the Emeralds of the Floating Island to reflect energy blasts Robotnik created using the Emeralds from the Sunken Island back at him, destroying his weapons and sending him back to Mobius Prime. Anti-Knuckles quickly replaced all six of the Sunken Island's Chaos Emeralds, saving the island, and then took the Freedom Fighters back to where they could make their own return trip. He was last seen with Evil Sonic in custody, but the Hedgehog's reappearance later on clearly states that Anti-Knuckles didn't hold on to him long.

Scourge's Takeover of Mobius
During Scourge's takeover and oppression of Anti Mobius, Anti Knuckles was amongst the many to fall to Scourge following a battle between the two.
 * It is unknown whether Anti Knuckles was killed or not.

Personality
Unlike the Anti-Freedom Fighters, who are versions of the heroes of Mobius Prime with no moral sense, Anti-Knuckles is different from Knuckles in an entirely different way: he is a pacifist.