Dragon Knight

Sacred Oath
Comments from the Finger: Some of the best paladin prestige classes come from 3.5, but they’re all very locked down to serving one type of dragon or another. This is a little more generic, and hopefully captures some of that ‘Dragon Knight’ feel.

Oath of the Wyrm

The Oath of the Wyrm is a covenant forged between paladins and powerful draconic masters, often ancient great wyrms. Paladins who take this oath, often known as Dragon Knights, pledge to protect the wyrm that becomes their benefactor, honor its principles, and add to its horde. In exchange, the dragon imparts some of its own power, allowing the paladin to assume the visage of a dragon to strike terror into their enemies.

Tenets of the Wyrm
Each ancient great wyrm demands different vows and services of their paladins. Red dragons might demand slaves to be brought to their lairs, while gold dragons might only ask that their paladins combat evil dragons wherever they travel. In general, however, draconic paladins tend to follow these core principles:
     The Dragon’s Scale. Protect the great wyrm that is your master. Inaction resulting in the death of your master constitutes your failing as a paladin and will result in your fall.
     The Dragon’s Wing. You are to travel far from the lair that houses your master to combat its enemies and steal from their hordes. Only by flying far are you to extend your master’s influence.
     The Dragon’s Tooth. Slay your enemies with the ferocity of a dragon. Those who follow in your wake should feel the might of your master through your actions.

Oath Spells
You gain oath spells at the paladin levels listed.

Oath of the Wyrm Spells

Draconic Alliance
When you choose this oath at 3rd level, you forge a powerful alliance with a draconic benefactor. Choose one type of dragon from the Draconic Alliance table. This choice determines parts of your Breath Weapon and Dragon Scales Channel Divinity options.

Draconic Alliance

Channel Divinity
When you take this oath at 3rd level, you gain the following two Channel Divinity options.
     Breath Weapon. As an action, you can expend your Channel Divinity to exhale with the destructive breath of a mighty dragon. Your draconic alliance determines the size, shape, and damage type of your exhalation. Each creature in the area of exhalation must make a saving throw, the type of which is determined by your draconic alliance. A creature takes 2d6 damage for each point of your proficiency bonus, or half as much damage on a successful save.
     Dragon Scales. As a bonus action, you can expend your Channel Divinity to plate yourself in dragon’s scales of the same color as your master. For the next minute, you have resistance to damage type associated with your draconic benefactor.
     Additionally, whenever you take damage, you can use your reaction to reduce the damage taken by 1d8. If the attacker is within 5 feet of you, it then takes damage equal to the same amount. This damage’s type is the type associated with your dragon benefactor.

Frightful Presence
Starting at 7th level, when a creature with a challenge rating of less than your level moves within 10 feet of you, you can use your reaction to invoke the auras of ancient dragons. That creature must take a Wisdom saving throw or be frightened for 1 minute or until it takes any damage. After a creature fails its saving throw against this effect, it is immune for 24 hours.
     At 18th level, the range of this ability increases to 30 feet.

Legendary Resistance
At 15th level, when you fail a saving throw, you can instead choose to succeed. After using this ability, you can’t use it again until you finish a long rest.

Great Wyrm
At 20th level, you can use your action to assume the perfect form of ancient dragons. For 1 minute, you gain the following benefits:

• You sprout scaled wings from your back, which grant you a flying speed of 60 feet.
• You have immunity to damage of your dragon’s type. 
• You can use your reaction when you take damage to reduce that damage by 1d8.
• You can use your breath weapon at will. 

Once you use this feature, you can’t use it again until you finish a long rest.

Sidebar: Dragonborn Paladins
Dragonborn paladins that swear an Oath of the Wyrm are often placed in special favor by their benefactor, and have advantage on Charisma (Persuasion) checks made against dragons. Additionally, their breath weapons use the damage of their Channel Divinity: Breath Weapon, and the higher of the breath weapon save DCs. Dragonborn paladins that are the same color as their benefactor are of the highest favor, and gain the following feature:

Favored of the Wyrm. While your Dragon Scales Channel Divinity is active, you can use your bonus action to extend your damage resistance to a friendly creature you can see within 30 feet of you. While that creature remains in this range, it has resistance to the damage type associated with your Dragon Ancestry. You can switch this target to another friendly creature you can see within range as a bonus action.

Changelog: 7/29/16: Tenets: Revised
Dragon Scales: AC benefit replaced with DR 1d8
Frightful Presence: Half your level, now your level. Affected creatures are immune for 24 hours
Great Wyrm: AC benefit replaced with Dragon scales benefit
Sidebar: Dragonborn Paladins: Added
8/6/16: Sidebar: Favored of the Wyrm added
8/8/16: Dragonborn Paladins use the same damage and save DCs for breath weapons.
3/25/17: Draconic Alliance: No longer offers passive damage resistance
Dragon Scales: No longer offers immunity; rather, it also deals damage to an attacker when you redice damage
Favored of the Wyrm: Works when Dragon Scales is active