How would it not be easy? Great Jin just showed up so they have very little time to adjust there military along with there own strategies to fighting in the current situation facing the entire wilderness. Not to mention that Great Xia has the strongest and most experienced military, no matter which branch you choose, where as Great Jin only has whatever Gaia decided to give them as default soldiers. Plus Ouyang has been planning this for a while so he has the advantage in terms of being able to very quickly go in and destroy without them understanding WTF just happened. Ouyang literally just boasted a few chapters ago that he very easily,because all of the buffs, has the strongest calvalry in the world(though to be fair,as I mentioned before, every branch/field of his military is most likely the strongest in their respective branch/field)which should be perfect for what I hope is a blitzkrieg style attack. But also kudos to Ouyang for basically fucking Di Chen over with 0 casualties while simultaneously moving the Guard legion exactly where he needs them(to attack Great Jin)and getting a bunch of free land. This hole dispute masterfully handled by Ouyang and really does show how far he has come as both a ruler and a schemer.
Kupkake