Shield of the Realm
Artifact — Equipment
If a source would deal damage to equipped creature, prevent 2 of that damage.
Equip 
Benalish glazeplate is stained with salts from the Rift Era and enchanted to deflect blows.
Manuel Castañón
Dominaria (DOM)
• #228Rulings
If a creature is equipped with two Shields of the Realm, 4 damage will be prevented. Three Shields of the Realm will prevent 6 damage, and so on.
(wotc • 2018-04-27)
If multiple sources would deal damage to the equipped creature at once (for example, several blocking creatures), 2 damage from each of those sources is prevented.
(wotc • 2018-04-27)
If multiple replacement effects would modify how damage would be dealt, the controller of the permanent being dealt damage chooses the order in which to apply those effects.
(wotc • 2018-04-27)
Rulings
If a creature is equipped with two Shields of the Realm, 4 damage will be prevented. Three Shields of the Realm will prevent 6 damage, and so on.
(wotc • 2018-04-27)
If multiple sources would deal damage to the equipped creature at once (for example, several blocking creatures), 2 damage from each of those sources is prevented.
(wotc • 2018-04-27)
If multiple replacement effects would modify how damage would be dealt, the controller of the permanent being dealt damage chooses the order in which to apply those effects.
(wotc • 2018-04-27)