When you get to Rathir, make your way up to the upper city and talk to the King there. If you pass a persuasion check, you'll immediately persuade him to provide you with a boat. Make your way to the lower city to get to the boat.
Get on the boat and when you land on the other side, talk to Commander Owaiglyn. He will tell you to gear up. Talk to him again when you are ready. You will start the battle up on the ramparts. Make your way to the S, towards the Quest Marker. You'll have to fight your way through a few Tuatha but that's nothing new. Keep going until you get to a room with two Tuatha Priests. Focus on one and kill him before going to the next. There are three chests in this room to loot in the corners of the room.
When you go through the gate leading NE from this room, watch out for the traps. You'll pass a swinging axe and then at the top of the stairs, to the left is a spinning blade trap. For some reason, if you loot it, it deactivates the trap. Just beyond the next swinging axe trap are blades coming out of the floor at regular intervals on either side of the room. Pass by those and then you'll come to a hallway with spinning blade traps on either side of the hall.
You'll pass onto a balcony. Two siege ladders will come up and Tuatha will flood the area. Thankfully, you'll have Alyn Shir who is much more useful in this battle. Get rid of the Tuatha and knock down their ladders by breaking the supports. Talk to Alyn Shir and then head towards the other door to the balcony. You'll be greeted by a worried Scout. Go through the door and down the stairs. To the right will be a couple of chests. Loot them and then head into the tunnel to the SW. There is a lone guard here and you need to take him out quietly. Make your way down the tunnel and at the end you need to take out the Tuatha either quickly or quietly. It's ok if you fail; you aren't actually penalized for it.
After you save or don't save the prisoners, you'll come to another balcony area that is exactly the same as the previous one except instead of having Alyn Shir with you, you have a group of nameless soldiers. Clear this balcony as well and then go to the next room. This room has numerous chests and a blacksmith's station. Take the time to loot and prepare if you need to. When you are ready, take the double doors to the Ramparts.
You'll be outside and there will be a Tuatha Priest and two Soldiers (with Faeblades, which makes them much tougher). Jump right into the fight because your allies won't last long and when they are gone, you'll have to fight them without any damage sponges. Once they are dead, run along the ramparts until a scene occurs.
Balor
This fight against the Witch Knight is a real pain. He hits hard and won't be stunned by your attacks. He also casts the tornado spell, has a lunge attack and a quake attack. The Quake attack ends with him teleporting to a tower in the distance while Balor comes over for a shot at you. When this happens, Tilera will create a shield bubble that you need to get into. If you don't you'll take significant damage (On hard, you'll outright die). It is possible to take the Witch Knight down before he has a chance to teleport away but to do so you need to have a very aggressive Fate Shift and a good amount of luck. If you do, though, you'll be happier for it. Remember to keep chugging your potions.
When the battle is over, you'll run into Agarth. He'll send you along your way to go fight Balor. You will actually visit quite a few rooms of similar style to the ones you were just in. In the first room, you'll encounter a soldier and a Priest (and Agarth). The next room will have a soldier on the bottom floor and two archers up stairs that will leave you alone if you kill the soldier in the corner of the room. Then you come to a balcony with three archers but they are shooting at Balor. Sneak up on them and kill them from behind. After that, you'll come to a room with two Tuatha and an ally.
The room after that has two Tuatha and a Prismere Troll. It isn't a particularly hard fight once you kill the Tuatha but watching out for both attack styles can be tough. In the room immediately after the troll will be some guards. Talk to Captain Mys and choose "Balor." Then you will get a new option called "Join Me." Choose this and then you will get a persuasion opportunity. Pass that and he'll surely die. Anyway, lead him up the stairs and wait for the Balor to swing his beam from you to the far side and follow the beam about half way to the giant rock in the middle. Hide behind it and let him sweep his gaze. Wait for it to travel over you in the opposite direction and then make the run for the doorway. Just because you are inside doesn't mean that you are safe so keep moving.
Just beyond the Balor will be a room with two Tuatha Zealots with Faeblades. Kill the two of them and in the room beyond, you will see a priest. He will summon a Niskaru Tyrant so kill him quickly so you only have to deal with the tyrant. Watch out though because you're in a tight space. Fate Shift, use electricity and kill him quickly. If that wasn't enough, it's time for a boss fight. Head back out to the Ramparts.
Balor Round 2
Balor is actually an easier fight than you'd think. When he starts out, he'll likely make his swipe attack. He'll pull one arm way back and then swipe with it. To avoid this, dodge all the way to the back edge of the platform. If he opens his eye, you want to dodge to the very front of the platform so that you're too close to hit. He also has a roar attack that will push you back and does a small amount of damage. You can't avoid it but you can block it. The last two attacks are attacks where he stabs downward at you with one or both of his claws. When he uses just one claw, it will always land in the same spot either slightly left or right of center depending on the arm. When he uses both claws, he will adjust his aim and you'll likely end up between them. Try to make sure that's the case. When he does either of these attacks, let rip on his arms. Remember that technically he's a Niskaru so use lightning, not fire. If you do enough damage, you'll stun him and he'll fall on the platform allowing you to hit his face. Deal as much damage as possible. When he gets back up, play defense again. You can try hitting his arms with ranged attacks if you'd like but it's probably only about a 50-50 chance of hitting because his arms sway so much. Anyway, when you've manage to bring him down his finisher will require a few button presses. The first two presses are just timed rather than something you repeat but then at the end you'll have to repeat a certain button for your XP bonus.
Kill him and then talk to Commander Omaiglyn to start Silence Falls.
