He is a hermaphrodite and was bullied, like Will, at a young age because of having both male and female characteristics. Toby identifies as male.
In The Most Unkindest Cut of All, he auditioned to replace Henry Condell and succeeds. He is taught by Kate when he stays at Will’s London Lodgings and falls in love with her. Toby succeeds in playing at the theatre and is tricked by Condell and Kempe that he must break off Kate and his engagement and move to Italy, leaving Kate single for life.
Due to him being a hermaphrodite, it’s possibly he was reverted back to being bullied in Italy and his fame in acting had been lowered once again.