I was wondering what's the strongest mage NPC in Skyrim. Like what one has the most spells or the master level spells? Who is the best? Is it the arch mage?
If you count shouts as magic, objectively speaking Miraak would be the strongest "Mage" as he knows:
- Fire Breath
- Frost Breath
- Bend Will
- Dragon Aspect
- Become Ethereal
- Whirlwind Sprint
- Unrelenting Force
Also his level is the player level times 1.1 (up to 150) so he'll always be stronger than you until you reach 151, which most other characters can't reach.
After that it would be the Solstheim Dragon Priests (Capped at level 60) who use actual spells. All other "mages" are significally weaker.