Grave Birthing

• WWizards of the Coast2015-08-25
  Official Ruling
  Other cards and abilities can give a card with devoid color. If that happens, it's just the new color, not that color and colorless.
• WWizards of the Coast2015-08-25
  Official Ruling
  Devoid works in all zones, not just on the battlefield.
• WWizards of the Coast2015-08-25
  Official Ruling
  If a card loses devoid, it will still be colorless. This is because effects that change an object's color (like the one created by devoid) are considered before the object loses devoid.
• WWizards of the Coast2015-08-25
  Official Ruling
  Some instants and sorceries that create Eldrazi Scions require targets. If all targets for such a spell have become illegal by the time that spell tries to resolve, the spell won't resolve and none of its effects will happen. You won't get any Eldrazi Scions.
• WWizards of the Coast2015-08-25
  Official Ruling
  Cards with devoid use frames that are variations of the transparent frame traditionally used for Eldrazi. The top part of the card features some color over a background based on the texture of the hedrons that once imprisoned the Eldrazi. This coloration is intended to aid deckbuilding and game play.
• WWizards of the Coast2015-08-25
  Official Ruling
  The target opponent chooses which card to exile as Grave Birthing resolves.
• WWizards of the Coast2015-08-25
  Official Ruling
  Eldrazi and Scion are each separate creature types. Anything that affects Eldrazi will affect these tokens, for example.
• WWizards of the Coast2015-08-25
  Official Ruling
  A card with devoid is just colorless. It's not colorless and the colors of mana in its mana cost.
• WWizards of the Coast2015-08-25
  Official Ruling
  You can cast Grave Birthing targeting an opponent with an empty graveyard. Even though that player won't exile a card from their graveyard, you'll still get an Eldrazi Scion and draw a card.
• WWizards of the Coast2015-08-25
  Official Ruling
  Eldrazi Scions are similar to Eldrazi Spawn, seen in the Zendikar block. Note that Eldrazi Scions are 1/1, not 0/1.
• WWizards of the Coast2015-08-25
  Official Ruling
  Sacrificing an Eldrazi Scion creature token to add is a mana ability. It doesn't use the stack and can't be responded to.

Rulings via Scryfall