Knight

Bonus Proficiencies
At 3rd level, you gain proficiency in one of the following skills of your choice: History, Insight, Performance, or Persuasion. In addition, you gain proficiency in the Animal Handling skill if you don't already have it. Your proficiency bonus is doubled for any ability check you make that uses this proficiency.

Alternatively to an extra skill proficiency, you can learn one language of your choice.

Unwavering Mark
Starting at 3rd level, when you hit a creature with a melee weapon attack, you can mark the creature until the end of your next turn. This effect ends early if you are incapacitated or you die, or if someone else marks the creature.

While it is within 5 feet of you, a creature marked by you has disadvantage on any attack roll that doesn't target you.

In addition, if a creature marked by you deals damage to anyone other than you, you can make a special melee weapon attack against the marked creature as a bonus action on your next turn. You have advantage on the attack roll, and if it hits, the attack's weapon deals extra damage to the target equal to half your Fighter level.

Regardless of the number of creatures you mark, you can make this special attack a number of times equal to your Constitution modifier (minimum of once), and you regain all expended uses of it when you finish a long rest.

Warding Maneuver
At 7th level, if you or a creature you can see within 5 feet of you is hit by an attack, you can roll 1d8 as a reaction if you're wielding a melee weapon or a shield, adding the number rolled to the target's AC against that attack. If the attack still hits, the target has resistance against the attack's damage. You can use this feature a number of times equal to your Constitution modifier (minimum of once), and you regain all expended uses of it when you finish a long rest.

Hold the Line
At 7th level, you gain the Sentinel feat, or another feat of your choice if already possessed.

Relentless Pressure
At 10th level, creatures provoke an opportunity attack from you when they move 5 feet or more while within your reach.

Ferocious Charger
Starting at 15th level, if you move at least 10 feet in a straight line right before attacking a creature and you hit it with the attack, that target must succeed on a Strength saving throw (DC 8 + your proficiency bonus + your Strength modifier) or be knocked prone. You can use this feature only once on each of your turns.

Vigilant Defender
Starting at 18th level, in combat, you get a special reaction that you can take once on every creature's turn, except your turn. You can use this special reaction only to make an opportunity attack, and you can't use it on the same turn that you take your normal reaction.