423.2. Cards may only be drawn one at a time. If a player is instructed to draw multiple cards, that player performs that many individual card draws.
423.2a If an effect instructs more than one player to draw cards, the active player performs all of his or her draws first, then each other player in turn order does the same.
432.2b If an effect instructs more than one player to draw cards in a Two-Headed Giant game, first the primary player (seated on the right) on the active team performs all of his or her draws, then the secondary player on that team performs all of his or her draws, then the nonactive team does the same.
423.3. If there are no cards in a player’s library and an effect offers that player the choice to draw a card, that player may choose to do so. See rule 413.2c.
423.4. A player who attempts to draw a card from an empty library loses the game the next time a player would receive priority. (This is a state-based effect. See rule 420.5g.)
423.5. If an effect moves cards from a player’s library to that player’s hand without using the word “draw,” the player has not drawn those cards. This makes a difference for abilities that trigger on drawing cards or that replace card draws, as well as if the player’s library is empty.
423.6. Some effects replace card draws.
423.6a An effect that replaces a card draw is applied even if no cards could be drawn because there are no cards in the affected player’s library.
423.6b If an effect replaces a draw within a sequence of card draws, the replacement effect is completed before resuming the sequence.
423.6c Some effects perform additional actions on a card after it’s drawn. If the draw is replaced, the additional action is not performed on any cards that are drawn as a result of that replacement effect or any subsequent replacement effects.
5. Additional Rules
500.1. Some effects restrict declaring attackers or blockers in combat or require certain creatures to be declared as attackers or blockers. (See rule 308, “Declare Attackers Step,” and rule 309, “Declare Blockers Step.”) A restriction is an effect that says a creature can’t block (or attack) or it can’t block (or attack) unless some condition is met. A requirement is an effect that says a creature must block (or attack) or it must block (or attack) if some condition is met.
500.2. As part of declaring attackers, the active player checks each creature he or she controls to see whether it must attack, can’t attack, or has some other attacking restriction or requirement. If such a restriction or requirement conflicts with the proposed attack, the attack is illegal, and the active player must then propose another set of attacking creatures. (Tapped creatures and creatures with unpaid costs to attack are exempt from effects that would require them to attack.)
Example: A player controls two creatures, each with a restriction that states “[This creature] can’t attack alone.” It’s legal to declare both as attackers.
Example: A player controls two creatures: one that “attacks if able” and one with no abilities. An effect states, “No more than one creature may attack each turn.” The only legal attack is for just the creature that “attacks if able” to attack. It’s illegal to attack with the other creature, attack with both, or attack with neither.
500.3. As part of declaring blockers, the defending player checks each creature he or she controls to see whether it must block, can’t block, or has some other blocking restriction or requirement. If such a restriction or requirement conflicts with the proposed set of blocking creatures, the block is illegal, and the defending player must then propose another set of blocking creatures. (Tapped creatures and creatures with unpaid costs to block are exempt from effects that would require them to block.)
500.4. A restriction conflicts with a proposed set of attackers or blockers if it isn’t being followed. A requirement conflicts with a proposed set of attackers or blockers if it isn’t being followed and (1) the requirement could be obeyed without violating a restriction and (2) doing so will allow the total number of requirements that the set obeys to increase.
500.5. When determining what requirements could be obeyed without violating restrictions, you don’t need to consider any options for a creature that don’t satisfy a requirement on it. But you do need to consider any options for any creature(s) that will satisfy a requirement, as long as the total number of obeyed requirements is increased (even if the option means not obeying another requirement that was previously met).
Example: A player controls one creature that “blocks if able” and another creature with no abilities. An effect states, “Creatures can’t be blocked except by two or more creatures.” The creature with no abilities isn’t required to block. It’s legal to declare both creatures as blockers, or to declare neither creature as a blocker, but illegal to block with only one of the two.
501.1. Evasion abilities restrict what can block an attacking creature. These are static abilities that modify the declare blockers step of the combat phase.
501.2. Evasion abilities are cumulative.
Example: A creature with flying and shadow can’t be blocked by a creature with flying but without shadow.
501.3. Some creatures have abilities that restrict how they can block. As with evasion abilities, these modify only the rules for the declare blockers step of the combat phase. (If a creature gains or loses an evasion ability after a legal block has been declared, it doesn’t affect that block.)
502. Keyword Abilities
502.1. Most abilities describe exactly what they do in the card’s rules text. Some, though, are very common or would require too much space to define on the card. In these cases, the object lists only the name of the ability as a “keyword”; sometimes reminder text summarizes the game rule.
502.2a First strike is a static ability that modifies the rules for the combat damage step. (See rule 310, “Combat Damage Step.”)
502.2b At the start of the combat damage step, if at least one attacking or blocking creature has first strike or double strike (see rule 502.28), creatures without first strike or double strike don’t assign combat damage. Instead of proceeding to end of combat, the phase gets a second combat damage step to handle the remaining creatures. In the second combat damage step, surviving attackers and blockers that didn’t assign combat damage in the first step, plus any creatures with double strike, assign their combat damage.