Eston has consistently demonstrated that they care mostly only about their own interests; that's what the treaty with Coria was all about, and I *dare* anyone to claim otherwise.
You can complain about Darka's relationship with Talerium all you want, but that was a known fact before the war even *started*. Eston pulled the rug out from its own allies mid-conflict so that it could cover its own ass. They basically started hedging against us all losing before it even really got until full swing.