When Rek'Sai (Queen of the Xer'Sai) is on the board, do champions played from the champion zone (like Volibear/Draven/Kai'Sa) come in ready, since the champion zone is not your hand?

Ruling: Yes, champions played from the champion zone come in ready when Rek'Sai is on the board, because the champion zone is not your hand.

Nuances:

• The champion zone being treated as "your hand" was a shortcut used to explain it, but according to the rules it is explicitly not your hand