Okdel L'da

Okdel was the leader of the Silurian triad of Wenley Moor, which included Morka (Young Silurian) and K'to (Silurian Scientist). He had developed a relationship with the Human Dr John Quinn. The Doctor convinced him that the Silurians could share Earth peacefully with Mankind. When he realized that Morka was trying to wipe out humanity with a virus, he freed the Doctor and gave him the means to find an antidote. He was then killed by Morka. (DW: Doctor Who and the Silurians)

Behind the scenes

 * Okdel was not named on-screen, only in the novelisation and in MA: The Scales of Injustice. He was listed as Old Silurian in the credits.