Need high level in Mechanics, first don't start combat through dialogue, go set a petrify trap close to the dragon, then cast Silent Scream to stun the dragon, after the combat started, quaff a potion of eldritch aim, then allure the wurm to the trap, and both of them will be petrified, petrified state will increase damage taken and directly to health, cast 2 shots of Mind Lancer to deal tones of damage(grazes for 148 pierce damage), then finish the sky dragon with a blunderbuss, of course the left wurm will share the same fate.

Edited April 1, 201510 yr by Emeus

What level were you when you killed him, and how many points did you have in mechanics / stealth?

Also, could you post your build?

Pretrify = win unless you just run in circles not attacking or some such nonsense. 

Petrify is currently insta-win button, yes. 

 

Sky dragon is still very doable on solo without it, however. Its damage output isn't that strong and it's also not particularly HP bloated, so given decent deflection and defenses (let's say, 70+) you'll be able to go toe to toe and live to tell the tale.

I wouldn't call it an insta-win button (you don't get many Gazes and the range is small), but it is a very effective boss-killer. I agree that you really don't need it for the Sky Dragon... but the other dragon in the game is basically asking for it.

You can buy the trap from defiance bay vendor every time you rest in the Inn , and mage can cast it like normal spell , yes its an insta win 

You definitely don't need petrify for the dragon.

Good. Now try the Adra Dragon