When you take the Attack action while unarmed, you deal an additional 1d4 of damage, which increases by one size as a level 5 (d6), 9 (d8), 13 (d10, and 17 (d12) guardian.
You gain resistance to bludgeoning, piercing, and slashing damage against mundane weapons and unarmed attacks.
You can take the Attack action as one action, but only twice on each turn of your turns.
When a creature takes the Move action within reach, you can take the Move action as a reaction to move towards he creature in a straight line, and if you move at least 10 feet and hit it while unarmed, you can take the Shove action as part of the same reaction.
When a creature takes the Attack action and critically hits you, you can take a reaction to make a Constitution saving throw (DC 10 or the attack roll total, whichever number is higher). On a successful save, the attack is considered a normal hit.