Warlord's Wager (2010)

The Warlord is the most powerful man in the world.

You need something that only he can give you.

He'll grant you a boon if you win his contest, but to do that you'll have to overcome all the other desperate men and women who have come to him because they have no other option. You don't know what the contest will involve, but you do know that if you lose, the Warlord will exact a terrible price.

Worse still, even if you do claw your way to the top of the heap, in order to get your wish you will have to defeat him in single combat- and no-one's done that in decades.

And that's assuming you won't fall foul of the other people who have taken his wager. Are they really there for the reason they say they are there, or merely giving a cover story that will satisfy the Warlord while they plot something more sinister?

(From back of book)