Rulings

• 2020-04-17
  The requirements of the companion ability apply only to your starting deck. They do not apply to your sideboard.
• 2020-04-17
  Before shuffling your deck to become your library, you may reveal one card from outside the game to be your companion if your starting deck meets the requirements of the companion ability. You can’t reveal more than one. It remains revealed outside the game as the game begins.
• 2020-04-17
  Your companion begins the game outside the game. In tournament play, this means your sideboard. In casual play, it’s simply a card you own that’s not in your starting deck.
• 2020-04-17
  If a replacement effect causes a player to exile the top four cards of their library instead of putting them into their graveyard as Gyruda’s triggered ability resolves, the creature card you choose may be one of those cards in exile.
• 2020-04-17
  A card with converted mana cost 0 has an even converted mana cost.
• 2020-04-17
  If a card in a player’s graveyard has in its mana cost, X is considered to be 0.
• 2020-04-17
  You may have one companion in the Commander variant. Your deck, including your commander, must meet its companion requirement. Your companion is not one of your one hundred cards.
• 2020-04-17
  The companion ability has no effect if the card is in your starting deck and creates no restriction on putting a card with a companion ability into your starting deck. For example, Zirda may be in your starting deck even if your other permanent cards don’t all have activated abilities.
• 2020-04-17
  If you reveal a companion outside the game, for as long as it remains there, you may cast it any time it’s legal to cast. Once you do, it comes into the game and behaves like any other card you’ve brought into the game. For example, if it’s countered or destroyed, it’s put into your graveyard, remaining in the game.
• 2020-04-17
  The companion’s other abilities apply only if the creature is on the battlefield. They have no effect while the companion is outside the game.
• 2020-04-17
  If more than one player wishes to reveal a companion, the starting player does so first, and players proceed in turn order. Once a player has chosen not to reveal a companion, that player can’t change their mind.