Infinite possesses the finalized version of the Phantom Ruby copies that is fused to his chest.

While his left eye is visible through a red visor, his right eye is covered by a black lightning bolt-shaped piece, similar to an eyepatch, that is connected to his mask's right ear, which glows red when he uses his power. He also wears pointed, metal and black hi-tops, with his personal infinity symbol engraved on the red soles.ДЄfter abandoning his old identity, Infinite began wearing a silver-colored mask with white and black circular patterns on the inside of the ears, with the right ear being black with white circular patterns and the left being white with black circular patterns. He wears a white collar around his neck and black gloves with silver designs on the backs, covering his sharp claws. There is a large white scar across the right eye. He has complete heterochromia, with his right eye being blue and his left eye being yellow. His muzzle is white and protrouding with cheek tufts, and he has a black nose and noticeable fangs. He has a white fur pattern on his back that resembles a ribcage, a bushy tail with five white tips, and long, white, stiff dreadlocks. Infinite is an anthropomorphic jackal with black fur. Late in Infinite's design process however, it was decided that his bandages and the scars on his mask were to be removed because they made him 'look weak.' Following then an adjustment in colors, Infinite reached his current design. This mask was given its patterns inside the ears (with one pattern on one side and the inverted colors on the other) because it gave it a geometric eeriness. It was also around this time that Infinite's mask began to take on its current form, albeit with scars on it. These designs included bandages to create an eerie sense of coolness. Infinite's species in particular, the jackal, was derived from Anubis, the ancient Egyptian god of the afterlife, who possesses a jackal head. The team later proposed a design using a buffalo motif, but it got scrapped in favor of his current jackal motif, which would settle as the outline for the character's design. A common element his early design shared with his final one was his mask and large hands with sharp claws. His original design was that of a ghost-like figure, with one of the examples including one with monster-like horns. Infinite went through several design changes.

Tanahashi noted as well that the design process was difficult, but that the silhouette of Infinite's face logo worked well during development. His overall design motif was derived from the Namahage, a demon-like being in Japanese folklore, with focus on key words like 'cruel', 'clinging to power', and 'not believing in bonds.' Since Namahages look scary, they also made for a cool and catchy silhouette that Infinite came to possess. Character artist Shinkichi Tanahashi later elaborated that Infinite was designed as a vicious existence that stood in the way of the bonds with friends that Sonic represents. Sonic Team was also peculiar about giving him a cool, but evil design, with his mask being designed especially to emphasize his evil nature. His nature likewise inspired the staff to elaborate on his origin story. This is the reason why he was made stronger and faster than Sonic the Hedgehog. ДЄccording to the producer of Sonic Forces, Shun Nakamura, Infinite was created with an impressive and strong presence in mind since he would be accompanied by old bosses in Sonic Forces. His final name ('Infinite') was intended to reference the nature of his ability. During the original drafts, Infinite was originally called 'Zero'.

Infinite warfare classic weapons list