In a tournament, if a player forgets to put their champion in the champion zone and it's discovered in their deck on turn 3 of game 2, what is the correct ruling?

Ruling: If the erroring player discovered the mistake themselves, it's a warning and the situation should be remedied by finding the champion and placing it in the champion zone. If the opponent discovered the error, it's a game loss.

Sequence:

• Determine who discovered the error (erroring player vs opponent)
• If erroring player discovered it: issue warning and fix by retrieving champion from deck
• If opponent discovered it: game loss penalty applies

Nuances:

• The number of champion copies matters for fixability - one copy is easily fixed, multiple copies may be harder if cards have been drawn
• This falls under deck presentation error rules
• The key distinction is who caught the error, as this encourages players to quickly correct their own mistakes