Not to mention that if Canterella is played on the very first turn, you can do one of two things:
1. Pass. Force the enemy to play a card to counter Canterella, and basically spend the card advantage they just got. If it was Menno, that means you won't have to deal with Menno later when you've superbuffed something. In fact, the only things they can play that result in gaining round victory in 1 card reliably are Menno and vanilla Geralt; anything else requires at least 2 cards to counter Canterella's strength (can't use Tibor when you've passed already, spending Joachim round 1 may yield you a medic or something else not entirely useful).
2. Decoy Canterella back. Game proceeds as normal. Maybe even throw your spy in the mix just to close out the round if they play a card. Or if Emhyr, just bring Canterella into your hand for use later.