I've just been through the whole of Beast of Winter, and I never found the Twin Eels unique greatsword. I was hoping someone could please tell me what I missed, because to a compulsive completionist like myself this is like a stone in my shoe. I remember there being a flooded area in the lower right-hand corner of the throne room in the Sunken Kingdom (?) that I couldn't reach; if that is it, how do I get there?

 

Any help would be very much appreciated.

That's exactly the place where you find it. You get there by not trying to go there. Everyone who has gone there had already removed the water by accident when entering the room, and everyone else has been unable to figure out how to do it.

 

In all seriousness, check this thread.

Thanks a lot. I went back there and managed to get it by starting over from the entrance and activating the first pedestal. When I re-entered the throne room the water was gone.