Viconia's Walking Fortress is a legendary shield that can deal 
Force damage when hit. Gives 
Advantage on saving throws against spells and 
Disadvantage to spell attacks made against the wearer.
'Walking Fortress' is a defensive technique reliant on a shield of this caliber. It involves upsetting your opponent who just wants to land a single blow.
Properties
+3
Armour Class
Required Proficiency: 
Rarity: Legendary
Weight: 2.7 kg / 5.4 lb
Price: 760 gp 
UID
MAG_TheBulwark_ShieldUUID
4f313dde-14bb-43a2-abdd-07b2eb38b33a
Special
The wearer of this item gains:
: When a foe hits you with a melee attack, you can use your 
Reaction to deal them 2~8Force damage and knock them 
unless they succeed a Dexterity 
Saving throw.- Spellguard
- You gain Advantage on Saving throws against spells. Spell Attack Rolls against you have Disadvantage.
: Can cast once per Short Rest.
: Can cast at Level 2, once per Long Rest.
Where to find
- Looted from Viconia DeVir during the quest Daughter of Darkness in Act Three.
Notes
As of v4.1.1.4425968 this item is bugged. Rebuke of the Mighty can trigger, but it has no effect. No Force damage is dealt, and no Prone condition is applied. The combat log will record the use of "Bash", but no save is rolled and no effect is ever applied.