Mogu? They seem like the elves, ancient and an over developed sense of entitlement. Everyone of Azeroth must learn, sooner or later, that the Horde is not "visiting" this world. We are here. We are staying.
Teach them this lesson. Quell their numbers in the ruins south and west of here. Break their amassing forces before they decide to attack.
Learn what you can of how these creatures fight, and how they die.