Guardian (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 now have the heavy property and because of your mastery, which grants a +4 bonus to your AC. In addition, you can make attacks with shields. You recieve the dual wielder feat but only works on your offhand weapon that is a shield. The damage die you use for your shield attack is 1d6 and it deals bludgeoning damage. At 7th, 10th, and 15th level, the die increases to 1d8, 1d10, and 1d12 respectively.
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. If a creature of your size or smaller is directly behind you, Ranged Attacks and Ranged Spell Attacks have disadvantage to hit them. Area of affect spells do not take disadvantage. 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, as a bonus action you may force all foes within a 30ft radius to direct their single target attacks and actions at you until the start of your next turn or receive disadvantage. If an area of attack affect attack or spell is used, then you must be targeted as the center of the attack or spell. 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) per short or long rest.
At 10th level, you create a safe area in a 15ft cube behind you when you enter defensive stance. Allies within this cube add your shield's AC bonus to dexterity saving throws they make against spells or other harmful effects. If you or an ally are subjected to an effect that requires them to make a Dexterity saving throw to take only half damage, they take no damage if they succeed on the saving throw.
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.