The Return of Riddles!!!

[WarBringer]

Hello all, I'm sad to say that I have not posted for almost a year, but I'm back! Now, my return had me thinking of all the great threads I used to see, and perhaps my all time favorite is the old Riddles thread. Now, if anyone knows of an existing riddles thread, please let me know, but if not, let the fun begin! I'll start things off with an easy one.
Here goes:

Two Kings
Relentless, Unwavering
Of Opposite natures, yet equal statures
do battle on this arena of symmetry and chaos
With a host to do their bidding
Yet in the end, defeat resides solely upon their soldiers
but the war never truly ends...

Who/What Am I?

[Encaitare]

Check out Riddles in the Downs... or Haiku Riddles if you happen to dig poetry.