First strikeFirst strike is a static ability that modifies the rules for the combat damage step. (See rule 510, “Combat Damage Step.”)
If at least one attacking or blocking creature has first strike or double strike (see rule 702.4) as the combat damage step begins, the only creatures that assign combat damage in that step are those with first strike or double strike. After that step, instead of proceeding to the end of combat step, the phase gets a second combat damage step. The only creatures that assign combat damage in that step are the remaining attackers and blockers that had neither first strike nor double strike as the first combat damage step began, as well as the remaining attackers and blockers that currently have double strike. After that step, the phase proceeds to the end of combat step.
Giving first strike to a creature without it after combat damage has already been dealt in the first combat damage step won’t preclude that creature from assigning combat damage in the second combat damage step. Removing first strike from a creature after it has already dealt combat damage in the first combat damage step won’t allow it to also assign combat damage in the second combat damage step (unless the creature has double strike).
Multiple instances of first strike on the same creature are redundant. (CR 702.7)
At the beginning of your upkeep,
revealTo reveal a card, show that card to all players for a brief time. If an effect causes a card to be revealed, it remains revealed for as long as necessary to complete the parts of the effect that card is relevant to. If the cost to cast a spell or activate an ability includes revealing a card, or if a card is revealed because an ability is activated from a hidden zone (see rule 602.2a), the card remains revealed from the time the spell or ability is announced until the time it leaves the stack. If revealing a card causes a triggered ability to trigger, the card remains revealed until that triggered ability leaves the stack. If that ability isn’t put onto the stack the next time a player would receive priority, the card ceases to be revealed.
Revealing a card doesn’t cause it to leave the zone it’s in.
A card that is currently revealed may be revealed again.
If cards in a player’s library are shuffled or otherwise reordered, any revealed cards that are reordered stop being revealed and become new objects.
Some effects instruct a player to look at one or more cards. Looking at a card follows the same rules as revealing a card, except that the card is shown only to the specified player. (CR 701.20) a card from your hand at random.