Some creatures have an armor value to the right of the card title. Armor prevents an amount of damage equal to the armor value that the creature would take each turn. Armor prevents damage before it is actually dealt. For example, if a creature has two armor and is dealt one damage, that damage is instead prevented by the armor, leaving the creature with one armor that can prevent damage left for the rest of the turn. If the creature is later dealt three more damage during that turn, one damage is prevented and the other two damage are dealt to that creature.
If a creature gains armor, the gains are additive and accumulate on top of the creature’s printed armor value.
If a creature gains armor during a turn, the gained armor does not prevent damage already dealt that turn. If a creature loses armor during a turn, it is not retroactively dealt damage that was already prevented by the armor.
If a creature loses any amount of armor, it loses armor that has been used to prevent damage this turn before it loses armor that has not been used to prevent damage this turn. If a creature has a “~” symbol in its armor field, the creature has no armor. Such creatures may gain armor through card effects.