Searched all over google and havnt found anything related to this.

Ive been trying to beat the Kayran forever now and (even not getting hit once) i always die right at the QTE because my life is constantly draining. Basically the boss is bugged/impossible to beat because my mongoose/quen is not working to remove the constant HP drain. It a huge drain and the only reason i can make it past a tentacle ot two is because im using the Dark weapons for the life on hit. During the QTE the screen just goes black for a bit (while im still doing the QTE until it gives me a game over.)

Anyone know how to fix this?

Try this tactic to beat the Kayran:
- Don't get too close, as at a certain distance it produces a poison cloud.
- Use Yrden to fix the tentacles to the ground (this only works for the four outer ones, not the inner pair).
- A fairly reliable location to place an Yrden is as close as possible to the yellow prompts that allow planting a Kayran Trap.
- Place an Yrden and position yourself in-line with the monster. Wait until Kayran strikes out and then dodge to the right or left. Once the tentacle is immobilized the Kayran stops attacking, so go and hit the glowing part with the silver sword.
- Sever the tentacle and back off.
- Use Quen only while a tentacle is immobilized and the beast isn't attacking.
- Repeat until the tentacles are gone and a cut-scene begins ...
- Now you have to follow the commands as fast as possible

(^_ it was bugged, Quen / Mongoose did'nt work)

-Id start off (while screen was still loading) running to the left, then drop a Yrden and roll left, before the first tentacle dropped. That left me with one tentacle down and full hp from life steal /w 2nd strongest dark wep)
-Then run to the statues feet, wait for him to hit bridge and drop 2nd Yrden where tip of the tentacle come down after bridge breaks) avoid/kill tentacle
-Then run along the outside of the "white line" (just out of range from his spray) all the way to the other side, hoping you dont get hit. Drop 3rd Yrden, run left, kill 3rd tentacle. (you should still have at least half hp)
-Run along the wall to the backmid, hope you dont get hit, spam Y to start QTE, spam X, A.. he breaks bridge.
-Start running immediatly to falling bridge, climb bridge for the kill.
-Dont get hit. If you get lucky and hit 3 times per tencacle (for life steal) you MAY be able to sacrifice one hit.
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oh my god i actually killed the bastard! Perfect run on hard, no hits, barely even a centimeter of hp left (2 seconds of playtime left, maybe?) of hp at the last cutscene.

Not sure if his poison is just really strong on Hard, or if my mongoose was just broken or what.. I don't remember the drain being anywhere near that strong on my first playthrough.. but he is beatable (with dark weapons and a lucky 3 ticks on a tentacle)

edit
Just checked, i didnt even use the mongoose, its still in my inv. Not like it made a difference..
I did use a swallow and one more. I think it was a Falkas Blood ( +10% dmg) for higher regen ticks on hit)

That's why it's so much better to play any Witcher game on hard (or even harder). It's satisfying now, isn't it ;-)

Its still doing it.
( i think it may have done it on Letho fight as well, though after dying once, (and getting curious) i dropped him so fast the 2nd time i never even noticed my HP and just put it up to maybe being hit with a dot or something.

Trying to beat the part with the magic owl and the undead. My hp is constantly draining. The only way i managed to beat it was by constantly staying outside the circle and killing them for HP regen. (and getting lucky at near death and gaining a lvl for full HP)

How do i fix this, its game breaking.
(is it supposed to do this on hard difficulty? if so then alright fine.. but im pretty sure a scripted fight sequence shouldnt require the lucky chance of gaining a lvl to complete?

I have better texture env/weps, dark items, dynamic hud, return of the white wolf (white hair), weight watchers (lowers weight amounts for herbs n such) and extreme quality flora (mod on in options) Those are all the mods im using.

any idea what could be causing this?

(EDIT)
OMG! Just found this thread on gamefaqs gamefaqs.com/boards/997903-the-witcher-2-assassins-of-kings/62628291?page=1

apparently the swords being drawn without the accompaning armor set drains your HP! LMAO!! (I lost my swords due to glitches with the mod, when having to remove my weapons for quests, and having kept going to lower and lowers lvl Dark Swords, but keeping the Kinslayers Armor Set on, it was putting a HUGE drain on my HP!

It was fun, and i really did enjoy the sense of urgency but, im so fixing this asap
Cant belive ive been playing through the game not knowing the mix match of swords/armor drains my hp.

Thinking maybe i should just uninstal the mod. (after i purchase new gear to make up for the lack thereof)

Gah, tricky one ;-) Haven't thought of something like this, because the fight can be though. Thanks for the heads-up.