One Wylde Knight by Kathryn Le Veque

The bigger and badder they are, the harder they fall…
Dark, sultry, with a hint of fire in his blood from his Visigoth ancestors and a spark in his eye that betray his killer instincts, Thorington “Thor” de Reyne is the son of the Earl of Ashington and one of the greatest knights England has ever seen. His talent is unmatched, so much so that the king himself has demanded Thor’s service.

But he has to fight Thor’s own father to get him.
Much in demand, Thor has an ego that is fed by the warlords and kings who are fighting over him. But he has own plans and that includes getting rich, rich enough so that he won’t have to serve at the whim of a king or an earl.
And the king knows it.