Sil

Sil is a minor antagonist in Season 16. He is a Mentor from the planet Thoros Beta and he loves to eat march minnows.

The Sixth, Fourth, Tenth & Thirteenth Doctors encounter him on his home planet, Thoros Beta in the fourth episode of Season 16 after they travel through a time portal to escape from Sutekh. It is here where they learn that Sil is dealing weapons to another planet.