Viserys can go through multiple back to back high level mage duels, then relax for an hour--not even sleep, but simply rest, and be good to go again.
@DragonParadox Do people just think Viserys can do anything with magic that common convention says should be limited, at this point? The spell casting everything without word or gesture, reaching into virtually every school and discipline, using Divine and Arcane...
At this point I guess the only thing we can't really do is fleshsmithing (identifying and maybe even cataloging the work of Fleshsmiths? Sure, he has Knowledge (Nature) and Knowledge (Arcana) high enough for it, but most of the work he would do would be more the result of Wishcraft and brute force).
And Artificing.
There's also the lack of Psionic powers.
But really, pretty much everything else is on the table. And we're pretty much experts at Ritual magic.
Put Lya, Viserys and Qyburn in a room together, and they could probably figure their way out of any problem.