Does hiding a card satisfy Legion?

No, hiding a card does not satisfy the Legion condition.

According to Rule 737.1.c.1, "Hide is not a subset of Play." Because the Legion ability specifically requires you to have "played" a Main Deck card (Rule 738.1.c.1), the act of placing a card face-down (Hiding) does not count toward this requirement.

Summary of the interaction:

  • Hiding a card: This is a Discretionary Action, not the act of playing a card. It does not trigger Legion.
  • Playing a card from Hidden: Once you flip a face-down card over to play it on a subsequent turn, that action does count as playing a card and will trigger Legion effects for any cards played afterward that turn.

This is confirmed by multiple RiftJudge FAQs (e.g., FAQ #8466, #5902, and #8500), which explicitly state that hiding a card does not enable Legion.