After you talk to Síle, you join up with her in the forest near where you investigated the shipwreck with Triss. She will mention something about keeping the Kayran in place while you go down to kill it.
The Kayran has six tentacles, the two on each side have growths in the middle that you need to attack. Before you can attack these tentacles, you have to go to the left or right of the Kayran and cast Yrden sign on the ground. When the Kayran moves its tentacle to strike, roll or move out of the way. The tentacle will be trapped by the sign, during which you can strike the swollen-growth part of the tentacle. Upon accumulating enough damage, a mini cutscene would be played to show the tentacle being cut off. After you have cut one of the tentacles off the Kayran will be enraged so just move to the side and avoid the main tentacles, which can kill you in one blow.
The Kayran trap can instantly sever one of the tentacles; place it at one of the highlighted locations and it'll take the tentacle off when it comes down.
After you cut off three of the tentacles, there will be a sequence of 3 separate QTEs (if you are on Easy difficulty, or on Normal/Hard difficulty with "difficult QTE" turned off, you would only be prompted with the second QTE)
- to climb up the sweeping tentacle.
- to stab at the tentacle.
- Contrary to popular belief and to the other fill-the-bar QTEs, you don't need to fill up this QTE bar. On Normal difficulty, a mere minimum of 4 clicks will enable the next QTE.
- There is a bug where the option will not appear if you over-left-click the QTE bar on some computers where there is situational graphic loading lag. Click just enough to fill the QTE bar, then wait, even if the bar appears to "unfill". The space bar option will eventually appear, and you won't be thrown into the bridge wall).
- to jump off the tentacle.
Upon successful completion of the QTEs, a cutscene depicting the bridge collapsing on top of the Kayran will trigger. You can choose to hide behind a chunk of bridge that fell off or run directly toward the ramp on the left edge.
- Should you choose the former, the Kayran will only throw rocks at you while you run between the bridge-chunk to the foot of the ramp. Cast Quen before running there as the rock can hit you easily. Once at the foot of the ramp, instead of throwing rocks at you the Kayran just hits you with the tentacles.
- Should you choose the latter, the Kayran will throw rocks at you as you run up the ramp.
While running up the ramp, keep to the left as the right side leads to a dead end. Attempting to cast Quen on top of the ramp is dangerous as you might get hit by the tentacles/rocks, it is safer to just continue running to the top.
Once you reach the top of the ramp, a cutscene will play and you will have defeated the Kayran.
- Only the glowing tentacles with bulbous growths can be trapped and cut off. Attempts to attack/trap the healthy tentacles (the two in the middle) will have no effect.
- Don't move too close to the left and right edge (marked by the blue barriers), or else the furthest tentacles will sweep at you or the lightnings will kill you.
- When the Kayran is enraged (each time after you cut off a tentacle), take shelter near where you jumped down to the Kayran's lair, or else one of the tentacles might hit you.
- The Kayran is lootable two times. Once from the left side of the Tentacle which the Sorceress examines, and once from the right side. (Edit: It seems that if you load the autosave from right after you defeat him, you will only be able to loot him once. Reloading didn't 'solve' it for me, had to beat him again for the double loot.)
- Kayran tentacle may block the path to the top of the ramp
- What about the monstrosity of Flotsam? Well, Geralt heard that the beast had attacked a man on the pier. Driven by professional curiosity, he went to investigate...
- Indeed, it was as the people had said - the unlucky victim lay on the pier. A riled crowd surrounded him and was commenting on the events. Among the onlookers stood the sorceress Síle de Tansarville. The witcher and the sorceress exchanged but a few words before she asked Geralt for help in hunting down the dangerous beast. First, they needed to identify the species. An elf named Cedric was said to be the most knowledgeable about the local wildlife.
- Cedric lived in Lobinden, a village nestled up against Flotsam's Walls. Humans paid him to keep the forest beasts away from their huts, so he spent most of his time on tree-top platforms gazing into the forest thicket.
- The witcher found the elf and questioned him about the monster. He learned that a poisonous mucus covered the beast, so that a single touch of its tentacle could fell a towering man. Geralt decided he needed an antidote, but to make this, he would first need a sample of the mucus. So he embarked on an expedition to the monster's lair, and Triss joined him.
- In the kayran's lair, Geralt learned that the monster's mucus was highly toxic. Triss gave our hero the formula for a potion that would render him immune to the beast's terrible venom, but he needed a herb known as ostmurk to make the draught. I've continued the story of the herb in another section, dear reader. Here you will learn how the hunt for the kayran progressed.
- After speaking with Síle, Geralt was ready to fight the kayran. armed with a sword and knowledge, he set out to slay the monster.
- You should have seen the battle! The bridge's arches crumbled like houses of cards and the beast's blood mingled with its poisonous mucus. Finally, the witcher, with much effort, won the day - the beast was dead, and our hero could pick up the reward he had rightly earned.
- Remember to loot the Kayran after the battle for valuable and useful items.
- The first part of the battle involves chopping off three of the creature's tentacles. Síle recommends Geralt "trap it with Yrden", by which she means to immobilize the tentacles, which are otherwise too dangerous to approach and too fast to hit. A fairly reliable location to place a Yrden is as close as possible to the yellow prompts that allow planting a Kayran Trap. Then, if Geralt is in the vicinity of that location (he does not have to be right on top of it), a tentacle will eventually contact the Yrden and be held (temporarily).
- Especially on higher difficulties where the damage done to Geralt per hit is very high, trying to keep Quen up tends to result in taking more hits because of the casting time. Instead, dodging is more useful until a tentacle is immobilized - at this point the Kayran stops attacking to focus on freeing its tentacle, and during that time it is safe to restore Quen.