The Dragon Knights are paragons of valor and leadership who partner with chromatic, metallic, or gem dragons. Such knights aspire to protect the innocent and rally fellow adventurers to the causes of justice and freedom.

Characters with this subclass are special among the order. Unlike most Dragon knights, who partner with dragons who’ve already reached adulthood, a  Dragon Knight character psionically bonds with an  dragon hatchling. This bond irrevocably transforms both dragon and knight, allowing the dragon to grow in strength alongside its partner knight.

Level 3: Knightly Envoy

You learn one language of your choice, which you choose from the language tables in the Player’s Handbook.
Additionally, you can cast the Comprehend Languages spell but only as a Ritual. Intelligence is your spellcasting ability for it.

Level 3: Dragon Companion

You are bonded with a dragon hatchling that serves as your dragon companion and uses the Dragon Companion stat block. The dragon is Friendly to you and your allies and obeys your commands.

The Dragon in Combat.
In combat, the dragon acts during your turn. It can move and use its Reaction on its own, but the only action it takes is the Dodge action unless you take a Bonus Action to command it to take an action in its stat block or some other action. If you have the Incapacitated condition, the dragon acts on its own and isn’t limited to the Dodge action.

Resurrecting the Dragon.
If the dragon companion has died within the last hour, you can take a Magic action to touch the dragon and expend a use of your Second Wind. The dragon returns to life after 1 minute with all its Hit Points restored.
Otherwise, you can perform a 1-hour ceremony to resurrect the dragon; this ceremony can be performed as part of a Short or Long Rest.

Shared Second Wind. When you use your Second Wind to regain Hit Points, the Dragon also gains Hit points equal to 1d6 plus your Fighter level 

Dragon Companion

Dragon Companion
Small Dragon, Neutral
Armor Class: 13 + your Intelligence modifier
Hit Points: 6 plus six times your Fighter level (the dragon has a number of Hit Dice [d10s] equal to your Fighter level)
Speed: 30 ft., Fly 30 ft.,
STR (Mod/Save)	DEX (Mod/Save)	CON (Mod/Save)	INT (Mod/Save)	WIS (Mod/Save)	CHA (Mod/Save)
16 (+3/+3)	16 (+3/+3)	12 (+1/+1)	8 (−1/-1)	13 (+1/+1)	10 (+0/+0)
Senses: Darkvision 60 ft., Passive Perception 11
Languages: Understands the languages that you know, telepathy 30 ft.
Challenge Rating: None (XP 0; PB equals your Proficiency Bonus)
Damage Immunities: Fire
Traits
Stalwart Bond. Add half your Proficiency Bonus (round down) to any ability check or saving throw the dragon makes.
Actions
Rend. Melee Attack Roll: +3 plus your Intelligence modifier, reach 5 ft. Hit: 1d6 plus your Intelligence modifier Force damage.
Breath Weapon (2/Day). Dexterity Saving Throw: DC 8 plus your Proficiency Bonus plus your Intelligence modifier,: as an action your dragon exhales a blast of elemental energy in 15-foot cone  Each creature in the cone must make a Dexterity saving throw against the save DC Taking 2d6 Fire damage on a failed save or half as much on successful save

Level 7: Dragon Rider

You and your purple dragon gain the following benefits.

Dragon Mount.
The dragon grows to Medium size. You can use the dragon as a mount if you are Medium or smaller, but while you’re riding it, the dragon falls at the end of a turn if it’s airborne and the only thing holding it aloft is its Fly Speed. It takes you only 5 feet of movement to mount or dismount the dragon.

Improved Breath Weapon.
The dragon’s Breath weapon becomes a 30-foot Cone. and its damage increases by 2d6 damage.

Dragon Cry. When you use your Second Wind to regain Hit Points, you can choose up to your Intelligence modifier of numbers of allies (minimum of one) within 60-feet Emanation originating from you. Each one regains hit points equal to your fighter level, provided that creature can see or hear. Also, when using this ability, the dragon regains its one use of its Breath weapon 

Level 10: Rallying Surge

When you use your Action Surge, you can choose up to Intelligence modifier number of allies within a 30-foot Emanation originating from you. Each ally can take a Reaction to use one of the following options.

Advance.
The ally makes one attack with a weapon or an Unarmed Strike. If your dragon is one of the allies using Advance, the dragon can make one Rend attack.

Retreat.
The ally moves up to half its Speed without provoking Opportunity Attacks.

Level 15: Enduring Commander

You and your purple dragon gain the following benefits.

Superior Mount.
The dragon grows to Large size, and both its Speed and its Fly Speed increase to 40 feet. Additionally, the dragon no longer falls at the end of a turn if airborne while you’re riding it.

Tandem Attack.
The Rend attack increases by 1d6 and Breath Weapon damage increases by 2d6 also, when you take the Attack action on your turn, you can forego one of your attacks to command the dragon to make one Rend attack. Alternatively, you can forego two of your attacks to command the dragon to use Breath weapon.

Level 18: Draconic Pinnacle

You and your dragon gain the following benefits.

Encouraging Presence. You, as well any allies within 10-foot Emanation originating from you, gain a bonus to melee weapon or Unarmed strike damage rolls equal to your Intelligence Modifiers (minimum +1)

Master of the Skies. The dragon grows to Huge size, and both its Speed and its Fly Speed increase to 60 feet also The Rend attack increases by 1d6 and the Breath Weapon's Damage Increases by 2d6 also the Breath Weapon becomes a 60-foot Cone.