Jason Hinderman
Companion to the Fourteenth and Fifteenth Doctor
Jason is a completely brand new and original character to the Legacy, being a Companion of the 14th & 15th incarnations of the Doctor. He only appeared once or twice in all of Legacy-verse.
During "Female of the Species" he was taken to be tortured as the kidnappers mistakenly believed him to be the Doctor based entirely on the fact that he was male and the only one seen exiting the TARDIS with the Doctor and River Song. It was this mistaken belief, while he had been brutally tortured, that led to everyone's lives being saved when the Doctor got them all out of the cage.
He left shortly after, although it isn't expressing mentioned, it assumed he did since he was never mentioned again.
During "Female of the Species" he was taken to be tortured as the kidnappers mistakenly believed him to be the Doctor based entirely on the fact that he was male and the only one seen exiting the TARDIS with the Doctor and River Song. It was this mistaken belief, while he had been brutally tortured, that led to everyone's lives being saved when the Doctor got them all out of the cage.
He left shortly after, although it isn't expressing mentioned, it assumed he did since he was never mentioned again.