Once you begin to cast Blood for Bones, no player may take actions until you’re done. Notably, opponents can’t try to remove the creature you wish to sacrifice.

Any abilities that trigger as the creature card is returned to the battlefield won’t resolve until after Blood for Bones is finished resolving.

Blood for Bones doesn’t target the creature cards to return from your graveyard. This means that, while the spell is resolving, no player may take any actions between the time you choose the cards and return them.

The creature sacrificed to cast Blood for Bones may be one of the cards chosen to be returned.

You must sacrifice exactly one creature to cast this spell; you can’t cast it without sacrificing a creature, and you can’t sacrifice additional creatures.