Spoiler:
Inside the Mouth of the Serpent, there is a gate that I cannot open. It leads to just a small cove, but inside I think I see a chest. Does anyone know how to open the gate?
This is the way in. Coming inside, you come down the stairs, you can open the gate from the levers. After a few steps forward, you will see a trip plate on the floor. This makes a log swing down upon you, hard,
At the four way, if you turn right you will see the gate.