Animated Armour

Second Slash. Upon missing on a melee weapon attack, the construct can exceed it's limits for a moment and expend a reaction to redirect it's weapon and take an additional Attack action on it's turn. The attack must be made against the creature the construct has missed.

Greatsword. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 17 (2d6 + 7) slashing damage. 

Defensive Pose. Whenever the creature's hit points exceed below half, it can expend it's reaction to turn to defensive mode. For the duration or until the mode is exited, it can add a 1d6 + it's dexterity modifier to it's AC. It cannot take any actions nor reactions whilst in this mode. The construct can use a bonus action to exit defensive mode. To return to defensive mode, the constructs health must be below half. After intentionally exiting defensive mode, a successful attack has to be made against it for it to be able to expend a reaction and re-enter this mode. The construct must be wielding a shield.