From Liquipedia Hearthstone Wiki
"Last Hero Standing" is a kind of match format announced by Blizzard for using in 2013 Innkeeper's Invitational at Blizzcon. The format is also used in 2014 Hearthstone World Championship.
- Matches are usually best of 5, with 3 classes per Eligible Participant each match.
- Each Eligible Participant will choose a class for the first game in a match, and the winner of the game will continue to use the class and deck that the winner was using when the game winner won the previous game until that Eligible Participant loses a game with that class before the Eligible Participant can choose another class and deck.
- The Eligible Participant who loses a game will no longer be able to use the class and deck that the losing Eligible Participant played during the loss for the rest of the match.
- The first Eligible Participant to win three (3) games will be determined to be the winner of the match.
- In the event that a game ends with both players “losing” simultaneously (“a Draw”), neither player will earn a game point. The match continues with each player using the same class and deck that was played in the Draw game.