Didymus or Thomas ("The Twin") is a title not a name. In some early sources he is referred to as "Judas called Thomas" ie Judas the Twin.
Out of all the sanitised figures in the gospels, only Judas and Thomas display real cynicism with respect to Jesus.
Historically, as opposed to mythologically, was Judas... Saint Thomas?
If the fairy tale death of Judas is false, that would explain why, after Judas' suicide, there are still 12 Apostles... Because Judas, the betrayer, is the same man as Thomas, the doubter, and he didn't suicide, or receive pieces of silver- he reconciled his faith and moved on... Possibly to India and China?
Historicity of Jesus is a fascinating subject.