The characters would likely be initially confused. Yugi might be shocked to see Sailor Moon's magical powers, while Sailor Moon could be intrigued by the dueling concept. They would start to learn from each other. For example, Tuxedo Mask could help Yugi with his strategy, as he is often a strategist in his own battles against the Dark Kingdom.
The Sailor Guardians and the Yu - Gi - Oh characters would interact in various ways. Some might form friendships based on their shared goals of protecting their respective worlds. The more brash characters like Joey Wheeler could get along well with Sailor Mars, as they both have a bit of a temper. And the more gentle characters like Tea could bond with Sailor Chibi Moon. They would exchange their skills and knowledge, with the Yu - Gi - Oh characters teaching the Sailor Guardians about card games and the Sailor Guardians teaching magic.