Tails constantly helps Sonic save the world from the evil Dr. Robotnik, and although he is young, he is a force to be reckoned with.
Tails looks up to Sonic as a brother, Sonic is older than Tails, and looks after Tails. His real name is Miles Prower, and he is a super genius, his robot building skills and engineering, rival that of Dr. Eggman himself. Tails may be young, but is a force to be reckoned with, and he constantly aids Sonic in his adventures. Tails and Sonic are best friends.
Tails has built many things such as robot fighters, aircrafts, even impressing Dr. Eggman. Tails is very young, only 8 years old, but this does not mean he cannot fight. In Sonic Battle, Tails fought multiple Gamma - like robots and won. Sonic has even trained Tails how to run faster and fight better in their free time in the beginning of Sonic Rivals 2.
Tails' real name is Miles Prower, although few people actually know this. In fact, when some evil robot were pretending to be Tails' parents, they called him "Tails", and that was not his real name. Sonic got suspicious, because if they truly were Tails' parents, they would have addressed him by his real name, and not the name that Sonic gave him.
The name Tails was given to Miles, by Sonic, because he is a fox with two tails, this nickname has almost substituted his real name, as few people even know his real name.
Tails has many abilities which he uses to beat the bad guys
Sonic the Hedgehog
The Sonic OVA's combined into a hour long movie released in America by ADV Films.