Awfully weak story... or is it? [WARNING:SPOILERS]

[Bloodclaw]

Actually, the Botany questline makes it clear that Gridania and the Ixal had peaceful relations for many, many years. Their current state of hostility is not explained, but Fufucha says nothing to indicate that it was Gridania that initiated those hostilities (which, given the fact that she is a fervent critic of the current conflict, would seem to indicate that Gridania didn't start that war). Additionally, Gridania very much wants peaceful relations with the Sylphs, who they have a treaty with and who are also a beast tribe.

So perhaps we have a traitor or two dozen amoungs our ranks that helped start the war between the 3 nations and the beast men.