Gather information, then use the Phial of Scrying to create a Scrying Bowl. Use the bowl to speak with Onu.
It is strange that the naga are here, in Darkshore. But stranger still...are the Twilight's Hammer. That cult worships the old, old lords of the earth. Lords defeated long ago.
The Master's Glaive, to the south, is a place where such an old lord fell.
Go there and look for more Twilight's Hammer cultists.
Take this phial of scrying. Use it to create a scrying bowl after searching the Master's Glaive. Then speak to me through the bowl.