Sentinel Knight

A homebrew subclass by InvokerTheOne or u/Thornspearr on Reddit.

Dressed in gleaming armor adorned with ancient sigils of protection, the Sentinel Knight emerges from the midst of combat like a guardian of old, their shield aglow with the promise of safety. With each step, the earth trembles beneath them, and the air crackles with anticipation.

In the heat of battle, their shield transforms into a formidable weapon, a seamless extension of their resolve. With each strike, it becomes a catalyst for counterattacks, a relentless whirlwind of retaliation. The Sentinel Knight's movements are calculated, their focus unbroken, and their timing impeccable.

As foes attempt to breach their defenses, the Sentinel Knight's reactions shine, turning every attack into an opportunity for retribution. With preternatural speed and precision, they intercept and counterstrike, leaving their adversaries in awe of their mastery of shield and sword.

The Sentinel Knight is a steadfast beacon on the battlefield, a bastion of defense upon which allies rely. They stand as the last line of protection, and their unwavering resolve serves as an inspiration to their comrades. In their presence, the tide of battle shifts, and the unyielding defense meets the unforgiving offense.

In the world of Dungeons & Dragons, the Sentinel Knight is a cinematic embodiment of unparalleled protection and unrelenting retaliation, wielding their shield and sword with mastery, and ever vigilant for the safety of their allies and the defeat of their foes.

From Defense, Offense

At 3rd level, you have become a powerful sentinel, capable of using shields as weapons.

Upon gaining this feature, you become capable of using your shield to attack. The shield attack does 1d6 bludgeoning damage and uses your Strength modifier for the attack and damage rolls, as well as additional bonuses if the shield is +1 or higher. (Treat it as if it was a +1/+2/+3 weapon.)

The shield also gains the Thrown property for you, with a normal range of 30 ft. and a long range of 60 ft.

The damage dealt by your shield increases as you gain levels in this class. At 5th level, the damage die becomes a d8. At 9th level, it becomes a d10, and at 13th level, it becomes a d12.

At 5th level, you gain the ability to use the Shove action as a bonus action.

Counterattack

Also at 3rd level, your capabilities with using shields have improved to a point where you can take advantage of a hostile creature's moments of weakness to deal damage and debilitate them.

When an enemy makes an attack against you or another creature within 5 ft. of you, whether it hits or misses, you can use your reaction to perform a counterattack with a one-handed melee weapon, your shield, or an unarmed strike. If you hit the enemy, they take normal damage and have disadvantage on attack rolls against all creatures other than you until the start of your next turn.

At 5th level, for every attack that has missed you in the last two rounds of combat, you gain a +1 to your attack and damage rolls for Counterattack.

Right Time for Everything

At 7th level, your martial prowess using a shield has transferred into counteractive social skills. You now know exactly what to say and when to say it to do what needs to be done.

Outside of combat, once per short rest, you can respond when spoken to by a creature, with a string of perfectly calculated words, intended to either charm or frighten them. They must make a Wisdom saving throw, and if they fail, you may choose to frighten or charm them for one minute. If they succeed, nothing happens.

During combat, you can instead expend a use of this feature as a reaction when a hostile creature misses you with an attack. You toy with them, using psychological warfare to show them that this is a battle they cannot win, or you goad them, causing them to become centered on you. They must make a Wisdom saving throw, and if they fail, that creature is frightened of you, or they cannot make attacks against any creature other than you. Both effects last for one minute, or until you are reduced to zero hitpoints.

The DC for either use of this feature is calculated as follows: 8 + your proficiency bonus + your Charisma or Wisdom modifier.

At level 10, you gain a second use of this feature.

Reactive Fortitude

At 10th level, your abilities as a Sentinel Knight are steadily improving. You learn to become more reactive in combat and can use your shield to greater effect.

When you use your Action Surge feature, you also gain a second reaction.

Additionally, when you make a thrown weapon attack with your shield and it hits the first target, your attack is calculated enough that it bounces to another hostile creature of your choice within 15 ft. of the original target. This requires a separate attack and damage roll.

At the DM's discretion, this may be used to bounce your shield off a wall or an object to hit an enemy you can't reach or see.

Mortal Defense

At 15th level, you have mastered the art of pattern recognition, and combined with increased reaction times and your Sentinel Knight abilities, you can easily avoid and parry consecutive enemy attacks.

When a hostile creature misses you with an attack, you gain a +2 bonus to your AC until the start of your next turn. This can stack if multiple attacks miss you, but only to a maximum of +6 to your AC. 

Avatar of Defiance

At 18th level, your abilities as a Sentinel Knight have peaked, and you have developed a nigh-mystical fighting method called the Defiant Stance.

Twice per short rest, as a bonus action, you can enter the Defiant Stance, which lasts for two rounds of combat (or 12 seconds outside of combat). When you are in Defiant Stance, you gain the following bonuses:
- Your AC is increased by 3.
- Every hostile creature within 15 ft. of you has disadvantage on attack rolls against any creature other than you.
- You have two reactions instead of one.
- When you use your Counterattack, the enemy has to make a Constitution saving throw against your Right Time for Everything feature's DC. On a failure, they are stunned until Defiant Stance is finished. The creature can repeat the saving throw at the end of each of its turns.
- Any attacks made with a shield have advantage.
- When you take the Dodge action, you and friendly creatures within 10 ft. of you have resistance to all damage types except psychic.

Additionally, you have mastered the technique of storing energy in your shield to use against your enemies. Once per long rest, you can unleash that kinetic energy as a powerful shockwave using an action. The shockwave can take the form of a 60 ft. beam (line) of energy, or a 30 ft. cone (your choice). Each creature in that area must make a Dexterity saving throw against your Right Time for Everything feature's DC. On a failure, they take 4d12 Force damage, plus an additional d12 of Force damage for every attack that missed you and every saving throw you succeeded in the last two rounds of combat, and are pushed back 15 ft. On a success, they take half damage.