Find and speak to Admiral Dvorek under the southern terrace in the Ruins of Vashj'ir.
Use Wavespeaker Valoren's sea horse to reach the forward post quickly.
The Admiral used the information you gathered for him to make a forward post under the terrace to our west. He's been preparing there for some kind of attack against the naga.
You should go to him immediately and inform him of the scope of what you've witnessed. Our force is small, and I fear for our soldiers if we charge in too recklessly.
Take my sea horse. It knows the way.