Aegis of the Bastion

Wondrous item, Very Rare (requires attunement by a creature proficient with shields)
This floating shield of black adamantine glows with a steady pulse of warding energy. Created by a forgotten order of guardians, the Aegis was built not to protect one warrior—but all who stand by them.

While holding this Shield, you have a +2 bonus to Armor Class. This bonus is in addition to the Shield’s normal bonus to AC.

The Shield has the following additional properties that you can use while holding it.

Floating Shield: The Aegis of the Bastion floats around you, requiring no hand to wield. 

Adamantine Core: Any critical hit against you becomes a normal hit while the shield is protecting you (And only you)

Protective Deployment (3/long rest): You may choose to have the shield protect an ally (as a reaction) within 30 feet of you causing you to lose the +4 AC bonus, but that ally gains it. The shield remains with them until you call it back (no action required at the start of your turn) or send it to another target (as a reaction).
-If this causes the attack to miss, the ally gains temporary hit points equal to 2d8 + your proficiency bonus

Forceful Bash: As a bonus action, you may reach up and wield the shield in one hand. By doing this, when you take the attack action, you can make one of the attack rolls using the Shield against a target (instead of a weapon or spell) within 5 feet of yourself (1d20 + Proficiency Bonus + Strength modifier) to the attack roll. On a hit, the Shield deals Force damage to the target equal to (2d6 + 2 + Strength modifier).
-The creature must roll a Strength Saving Throw (DC 16). If it fails, it is also pushed 10 feet directly away from yourself and knocked prone. If it succeeds, nothing happens.

 

NOT ACTIVE

Following "DM's Discretion" on when this becomes active (Memories return, Blessing from Raven Queen, etc.)

Emergency Override (1/long rest): When an ally within 30 feet of you would drop to 0 hit points, you can use your reaction to have the shield teleport instantly to their side and form a glowing dome of energy.
•That ally instead drops to 1 hit point.
•Until the start of your next turn:
o The ally gains resistance to all damage.
o Enemies have disadvantage on attack rolls against them.

Shields require the Utilize action to Don or Doff. You gain the Armor Class benefit of a Shield only if you have training with it.

Notes: Bonus: Armor Class, Immunity: Critical Hits, Requires Attunement