Just giving a heads up here.. the undead are currently inactive on Mist Harbor. The ritual was able to be completed.

So the way it worked was... a hidden room (you found it by SEARCHing in the room the entrance was in) was located on one of the islands in the Eastern Harbor (the Black Sands specifically).

In that room was a locked chest. I don't know the difficulty, but I don't think it was super high end.

In that chest was a weathered Jaston statuette (nothing fancy.. don't forget about 340 items Quilic! you could have made it appraise as having the presence of Jaston!).

The statuette was taken to where Fyodar hangs out (the deed room on FWI) and once it was put on the altar the siege was over.

Anyways, just sharing the details :)