Creating an LoL/DotA/WoW-inspired arena battle

[Kafana]

In my setting, the aventi are an underwater race which settle disputes through sports, by besting their opponent in a way which is most fitting for the dispute.

Now, when a there is a serious dispute (one which might result in a civil war in kingdoms of other races), the aventi would collect champions to fight for them in an arena. Basically, League of Legends.

I thought it might be interesting to have my players partake in such a battle, but I wanted to see if there are any systems which might support this idea, so that I don't have to invent the whole system from scratch.

What I currently have in mind:
- Some form of area control game, where the players need to win small skirmishes (which are essentially encounters) in order to conquer new territory (objectives), while defending other parts of the area in order not to lose territory;
- A "respawn" mechanism, so that players can play for objectives (and not their life);
- A "powerup" mechanism, so that good moves empower themselves, while bad moves empower the enemy.

There might be a board game that I'm unaware of, which offers something similar, so if you can suggest that as well I'd be grateful.

[Demidos]

...Laser tag IRL?

You could try Kemet as a board game. Risk might also be a simple option.

[Spookykid]

Bloodbowl!