The ongoing war is between the Whitherwater kingdom alliance and the Zebra lands. The official report is that the Zebras began to encroach and claim pony lands on the border of Haunchhock.
The war is now in the pony's favor, and having their lands back they plan to take some of the zebra provinces too.
They are recieving support from Blood in the form of war machines. The war is also being funded by the Jewel family.