
If you're having trouble with Kniles, and you are inside the prison, you can climb up the stairs that take you to the ground floor of the fort.
There on the beach (underneath the treasure chest which you can teleport to yourself) is an entrance into the Dungeon level of Fort Joy.
You can also teleport down next to where you first found Fane. The way forward through the pipe is open afterwords. He will ignore you after that, avoiding the battle. Alternatively, you can give Atusa's Leg to Kniles if you have it on your person when speaking to him. You can escape Fort Joy through this sewer. Kill him and use the key on his body to open the gate to the sewer. There you can find an enemy called Kniles the Flenser. You can then make your way to a lower floor to the prison. Push the ladder down and sneak into the fort. You can also use the Gloves of Teleportation acquired from the quest The Teleporter to teleport one of your party members to the second level of Fort Joy (south of the gate guarded by 4 magisters). Get into the prison by either letting yourself get caught by removing your collar and being seen by a magister ( The Arena of Fort Joy), or through the ancient tunnel (learn the location by completing The Imprisoned Elf), or through the quest Withermoore's Soul Jar (not needed to find the tunnel). You will find yourself at the beach, on the other side of the coast. If you choose to go north once inside the gates, you can meet a paladin near the port who is also fighting magisters. The straightforward way is to kill the 4 magisters at the gate, pick up the key, make your way inside the fort, then you can fight your way out. There are multiple ways to escape Fort Joy:. This quest is automatically acquired at the start of Chapter II. Escape from Fort Joy is a Quest in Divinity: Original Sin II and it is formerly known as The Escape and Fort Joy.