Advice request - Kairos v. Oxyotl, IE Campaign

I've restarted a couple Kairos campaigns now, and I always hit a wall with Oxy. Usually it's between turns 10-15 either he's declared war or I try to get the jump on him. Either way, it does not seem anything I can recruit up to that point can stand up to his army. Worse--he seems to straight-up hard counter anything I can bring, outranging my own ranged units, outrunning any melee, and smashing me up with big dinos.

He's very hard to ambush, so I'm a bit stumped. I have had some very close engagements with him, but I always seem to get really screwed over by his single entities--skink oracles, priests, and stegadons. My army has a really tough time killing them.