Hymn of the Wilds

• WWizards of the Coast2016-08-23
  Official Ruling
  Conspiracies are never put into your deck. Instead, you put any number of conspiracies from your card pool into the command zone as the game begins. These conspiracies are face up unless they have hidden agenda, in which case they begin the game face down.
• WWizards of the Coast2016-08-23
  Official Ruling
  If there are additional costs to cast a spell, or if the cost to cast a spell is increased by an effect, apply those increases before applying cost reductions.
• WWizards of the Coast2016-08-23
  Official Ruling
  A conspiracy doesn't count as a card in your deck for purposes of meeting minimum deck size requirements. (In most drafts, the minimum deck size is 40 cards.)
• WWizards of the Coast2016-08-23
  Official Ruling
  The first creature spell you cast each turn doesn't necessarily have to be the first spell you cast. For example, you could cast an artifact spell and then cast a creature spell that would get the discount.
• WWizards of the Coast2016-08-23
  Official Ruling
  If the first creature spell you cast in a turn has in its mana cost, you choose the value of X before calculating the spell's total cost. For example, if the first creature spell you cast in a turn has a mana cost of , you could choose 1 as the value of X and pay to cast the spell.
• WWizards of the Coast2016-08-23
  Official Ruling
  The first ability doesn't change the mana cost or mana value of any creature spell. It changes only the total cost you actually pay.
• WWizards of the Coast2016-08-23
  Official Ruling
  Conspiracies aren't legal for any sanctioned Constructed format, but may be included in other Limited formats, such as Cube Draft.
• WWizards of the Coast2016-08-23
  Official Ruling
  A conspiracy's static and triggered abilities function as long as that conspiracy is face-up in the command zone.
• WWizards of the Coast2016-08-23
  Official Ruling
  You don't have to play with any conspiracy you draft. However, you have only one opportunity to put conspiracies into the command zone, as the game begins. You can't put conspiracies into the command zone after this point.
• WWizards of the Coast2016-08-23
  Official Ruling
  If you have more than one Hymn of the Wilds in the command zone, their abilities will each apply to the first creature spell you cast each turn. For example, if you have two, the first creature spell you cast each turn costs less to cast. Subsequent creature spells won't get a discount.
• WWizards of the Coast2016-08-23
  Official Ruling
  The ability can't affect the amount of colored mana you pay for a spell. It reduces only the generic component of that mana cost.
• WWizards of the Coast2016-08-23
  Official Ruling
  The cost reduction can apply to an alternative cost, such as a madness cost.
• WWizards of the Coast2016-08-23
  Official Ruling
  You can look at any player's face-up conspiracies at any time. You'll also know how many face-down conspiracies a player has in the command zone, although you won't know what they are.
• WWizards of the Coast2016-08-23
  Official Ruling
  Conspiracies are colorless, have no mana cost, and can't be cast as spells.

Rulings via Scryfall