this will be one on one fights using your powers chosen by two different nation members or even 2 people of the same nation for example
make a topic called

Blackhawk120 Vs. ryugax or
even Monkehaha vs Blackhawk

you may chose who you want to fight if we have enough people i will conduct a tournement leading to the the 5 nation champion yes it souns extremely corny but i was bored