At the bottom, just behind the cage are some steps you can use to get onto the wooden platform. Take the cage at your 12 o’clock (instead of the one on the left) and ride it down. Then, follow the path beside the enemies you just defeated, down some steps that lead to cages you can ride down to the swamp.
Take out all the Dreglings at the top to trigger a cutscene. Behind him is the Prison of Hope, Special Key, which you can use to free the Sage Freke NPC on the third floor of the prison. Now, head up to the other tower (identical to the one you just went through) behind the ballista machine and follow this path all the way up, to the church, and to an enemy Dregling that you need to kill in order to defeat the next boss (if you don't the boss will be healed while you fight her so don't listen to anything he says). You can now turn it off to collect the items in front of it, safely. Open it and keep going into the tall tower, through the fog gate on the bottom floor, which leads to the backside of the deadly bolt machine. Follow this path along to the left and you’ll coupe to a double gate. Now, head back to the locked we mentioned above and open it using the Warden’s Key.
Go left and then right, straight towards the ballista machine and grab the Prison of Hope Warden’s Key - located on the ground just before you’d take damage.
