Guardian, Variant (5e Subclass)
From D&D Wiki
The archetypal Guardian is a master of defense who puts the well-being of his allies above all else. Guardians are resilient and near impenetrable iron walls that stand in the way of all opposition while still dealing heavy damage on the battlefield. It takes more than your average foe to take these juggernauts down.
When you choose this subclass at 3rd level, you gain the ability to wield shields with great prowess. Your shields must have the heavy property and because of your mastery, grant a +4 bonus to your AC. In addition, you can make attacks with shields. You recieve the dual wielder feat but only if your offhand weapon is a shield. The damage die you use for your shield attack is 1d8 and it deals bludgeoning damage. At 10th level, this increases to 1d12.
At 3rd level, as an action you can take an all-out defensive stance when you're holding your shield. While you're in this stance, you have resistance to all damage except psychic and add your proficiency bonus to your AC.Your movement speed is halved when you are in a defensive stance. This stance lasts until the start of your next turn.
Starting at 7th level, you may take an action to force all foes within 30ft to direct their single target attacks and actions at you for five rounds. All targets affected must make a Wisdom saving throw against your Persuasion (charisma) check. You can use this a number of times equal to 1 + your Charisma modifier (minimum 1 time) before needing to take a short or long rest.
At 10th level, you can use your reaction to intercept an enemy's attack targeting an ally within 5 feet of you. You can use this a number of times equal to 1 + your Strength modifier + your Dexterity modifier (minimum 1 time) before needing to take a short or long rest.
At 15th level, you can no longer be critically hit, any attempt to knock you prone has disadvantage and the distance you can be shoved is halved. Also you can now hold your defensive stance for one minute.
At 18th level you may enter a defensive stance as a bonus action instead of an action. When you enter a defensive stance you may add double your Strength modifier to your total AC.