Shardovan

Shardovan was an individual created by the Master when he also created Castrovalva.

Biography
Shardovan was the librarian in Castrovalva and one of the first people to question the Fifth Doctor when he awoke there. Shardovan died when he destroyed the Master's Hadron web which used Adric's ability with Block Transfer Computation to create Castrovalva. (TV: Castrovalva)