What (who) is take on a bet - definition

Bet On Soldier: Blood Sport is a first-person shooter video game developed by French developer Kylotonn and published in the North American and UK market by Digital Jesters. The story revolves around an unknown world war where elite soldiers meet each other in a battle to the death in one-on-one deathmatches. These deathmatches are broadcast all over the world as a televised sport named "Bet On Soldier" and since has become the favorite form of entertainment with many viewers betting on soldiers.

The game is billed as a spiritual sequel to the alternate history first-person shooter Iron Storm and heavily relies on assets recycled from the cancelled sequel. As a result, although it is not explicitly stated that the games take place in the same fictional universe, they share many of the same themes, plot elements, character and level designs, weapons, and even insignia of the fictional west European union.