Based on the character of the same name from Doctor Who (1983-84)
His first name is Vislor. But he uses that like once in his last episode and that's it. So I didn't bother calling him by his full name. He's just Turlough.
He's very suspicious and sneaky but also sad.
And he has some questionable judgement about saving people after they've fallen into a large body of water.
I mean compare this:
(The Doctor is pushed into the water. Tegan tries to save him. It's been 30 seconds max.)
TURLOUGH: There's nothing we can do! Face it, Tegan! He's drowned!
With this:
(Sees Peri struggling in the sea. Takes the time to take off his shirt and shoes before eventually jumping in to save her.)
(By the way I feel the need to mention that this is fiction and if you see someone struggling in open water it's not at all a good idea to jump in to save them because then you're endangering yourself as well as them. Just a little safety disclaimer.)
He's also an alien.
Played by Mark Strickson