Use the Blade of the Naz'jar Battlemaiden at the battle site at the southeast end of the ruins.
The shard you recovered looks to be of naga origin. I had hoped to find a strong focal object like this for a spell I've been working on that would allow us to glimpse into the recent past.
I've enchanted the blade, but you'll have to take it to a place where we know its owner was. I want you to travel back to the site where you found it and use the blade.
Perhaps we can uncover more behind what the naga are doing here. Or even better, maybe we'll uncover a weakness that will give us a better chance.