Board & Card Games Stack Exchange is a question and answer site for people who like playing board games, designing board games or modifying the rules of existing board games. It only takes a minute to sign up.
Description of situation: A player's turn begins and they draw the last card from the deck and get a Wizard. The use the Wizard on the other player which forces them to discard their hand and redraw it. There are no more cards to draw. What happens?
The way my group played is that the player who has to redraw is automatically eliminated because they must first "discard" to get rid of their hand, but no card to draw means they will not have a card for the final showdown.
According to the rules. A single card is to be removed from the deck at the start of each round. This removal serves two purposes. The first is to remove perfect information. So that in the final rounds you can deduce the likely card your opponents have but not necessarily with 100% certainty. The second is to be used in situations like you describe. If you need to draw a card for the final action that card is the card which was removed from the game. Then you compare numbers and establish a winner of the round.