(Warning, spoiler)

In many attempts to defeat Dettaff in the second phase, he throws bats that kill Geralt in one blow. I don't know how to get over that. Any tip? Here is one of my attempts

https://youtu.be/wvFbglaKW2A

Timing and dodge. That's the only way I know of not getting smoked. In your video you were *much* too close to him to be able to time and dodge properly. You don't want to be anywhere near him until he becomes immobile on the ground momentarily. That's the time to strike and then get the hell away.

Jump to 0:30 in the video. Geralt runs to a small rock. From here you are able to see the bats gathering at Dettlaff's position, and you can hear it. Then Geralt has to roll out of the way immediately.

https://www.youtube.com/watch?v=BbA6exUv-pY

If you can't see it then believe your ears.

Good luck

Roll to the side when you see the bats gather.

Finally, I got it... running cowardly. When Dettaff is going to launch the bats attack, I run looking to the vampire. And works. Also, I used Aard to get down the vampire when he is making a ground attack.

The third phase is easy.

Thanks for your help