Kang: When facing Kang, can a Depowered Dr. Strange still use his Invocations?

Yes, Dr. Strange can still use his “Spell Mastery” ability because he is not ‘playing’ the top card of the Invocation deck – he is resolving its ability. I can see how it might look unthematic, but from my experience with the books, Strange’s mystical knowledge was something that set him apart from other heroes. When others lost their powers, he could still summon his magic. I guess it’s up to the reader to interpret.

-Caleb