Formless One Bug

God dammit. 

Just like manaknights said. It works. Thanks 6qjvufnixzaw!

ok, so I found if you are using something like wemod, pausing the game, and then alt tabbing out to stop we mod while the dragon is perched, will let it move on. once it hits the ground again, if you just turn on wemod, attack and repeat, you can get past the bug and still use the mod. For those that have fun using it to get through the story. :)

The problem is third party program, if u still wanna use it,
Use it when u fight and stop it when he fly to the place its get stuck,
when u will do so its will let u continue the fight (u do it twice between stages

I did enjoy the fight without any third party but it is indeed hard fight.

I can confirm this, ty HausOfNadav...

 I used WeMod and I had to pause the game everytime the formless one went to the cliffs, click the "x" to stop WeMod's cheats from being enabled, then go back into the game, unpause, dodge everything I could and within about 5-10 seconds The formless one proceeded to call henchmen (Undead) and come back down again to fight in the arena. I then paused again, re-enabled the cheats an fought him until he went back to the cliffs. I repeated this process two times in total to kill him.