Prepare with mentioned stuff above here is a method to fighting melee but strongly suggest you keep fighting and figure it out yourself when yagltuh does Nova with right hand, run to left side of his body positioned between his left hand and spine-tail just outside of melee distance and the nova should miss you, as he turns to face you his left hand will be hittable without getting struck by his nova aoe. You should be able to get a 3 hit combo on his hand and then on his face usually and maybe more of he decides to sit there for a bit. When he raises his right hand and says party look up to the sky to watch the meteors while running away from where meteors are heading. If you stay close he should just keep going between those two attacks. Sometime he will do a ray usually if out of melee range, just strafe either direction. Once you get used to the timing of how long his ray goes you should be able to run strafe close to him and start hitting him just before he catches up to you and finishes raying. This is a safer method of melee fighting. if your fully prepping as mentioned with Stam, health, fire pots and good food it should be a breeze. fenris armour for speed and extra fire resistance is an option you might consider aswell, especially if you forget to reapply fire resistance mead during battle.