This fight left me stumped for a bit. I never noticed the falling tower in the top right corner. If you're here googling then you probably didn't either. This is an easy fight once you notice that part. At 50% Kablar will fly into the air. Run into the top right and you will see the big black pillar fall. Cross over it to the next stage.

This part is super easy if you save your mobility skills. Just kill the chains until you reach the end. If Kablar catches you then he will kill you. Pretty sure it's an instant 1 shot.

The last part is easy as well. I've marked in the screen shot below the order I do the fight in. 1 and 2 you need to interact with the area. It will shoot a chain onto the boss. You should see the prompt to interact when you get close. The chains will go away if you're too slow. So get both chains on the boss then run to 3. You have to stay on 3 until it finishes and then the boss is just a tank and spank

I feel like the Pagan Online boss fights are well done, but they need some kind of indicator of what you're supposed to do. Once you understand them they are super fun.