Nine is one of the several variants of Miles "Tails" Prower that was created when Sonic had accidentally broken the Paradox Prism.

After Sonic left, and everyone returned home, Nine was left by himself, with no one trusting him after the stunt he had pulled with the Paradox Prism.

Not only that, but with the Chaos Council back in business, and seeking revenge, being on your own is the least of his worries.

Credits:

Miles ‘Nine’ Prower belongs to Sega.

Art belongs to prove22222 on DeviantArt