Who are the kingmakers?

not sure, i dont even know what that is

Varys or Little Finger

In the game of checkers
when one reaches the other
side with a checker, The one player will say King me...
and the other player will put another checker on top
...Kingmakers??...LOL

Usually the head of the party and the party's executive committee. They decided the policies. They choose who stands as candidates. They design the campaigns, select the marketers and speech writers, and organise the fundraisers and press releases. The bigger the party, the more people are involved in specialised roles.
The Greens are the only party where the policies and candidates are decided democratically by all the members collectively.