This is the second boss fight. It took me roughly two hours to beat this witch. There was a point where I really thought I was never going to get past this fight and then it all began to click.
The video might give the impression that it was easy, but not for me. It took a while for me to figure out the right strategy. I started off by experimenting with different weapons, different armors and different charms. Those helped but it ultimately boiled down to the proper tactics. This is going to be a long game!