Guthred

Guthred meets Uhtred as a fellow slave, chained and starving in a mining pit, seemingly nobody in particular. He turns out to be Danish-born royalty, marked by prophecy as Northumbria's future king, and he is quick, charming and practical about using anyone — including Uhtred — to climb out of the pit and onto a throne.

Thure Lindhardt plays him as genuinely likeable and genuinely untrustworthy at once, a man who means his gratitude in the moment and abandons it the next when survival or ambition demands it. That slipperiness, worn with such easy charm, makes him one of the show's most useful tests of Uhtred's judgment about loyalty.