That's nuts wharn he's so hard to kill as a dragon. I may not be able to finish the game without a creature, but I'm trying. Necromancers fully creep me out.
Even in dragon form, its not that hard to take him down. Shoot him with fire sphere and chase up to him and use fire breath while your fire sphere in cool down and can pretty much take it down easily. Did you invest any points in your dragon skill? If you find it tough, maybe lvl up few more lvl and come back for him later. Dont tell me you dont even had your pet yet even you in fjords now? The necromantic pet is a very important companion that helps alot through out the adventure. You can choose not to learn summons but not having the necromantic pet or utilizing it is really a pretty silly move.