Dragon knight

A Dragon Knight is a fighter whose soul is suffused with draconic energy. Also called dragonriders, these fighters can use that energy to create a special kind of dragon, a manifestation of their draconic soul. They ride these dragons into battle, fighting as one, for the dragon is an extension of themselves. These warriors have a deep rage deep within their souls, fueling the strength of their dragon. Unlike barbarians, this power is much more magical and stems from the soul, and a deep connection with dragons. Dragon Knights are almost always found adventuring, channeling their draconic fury into whatever cause they deem fit.

Dragon companion

At 3rd level, you can magically manifest your inner dragon. As an action, you can summon a dragon steed, which appears in an unoccupied space of your choice that you can see within 30 feet of you.

The dragon steed is friendly to you and your companions and obeys your commands. See its game statistics in the Dragon steed stat block, which uses your proficiency bonus (PB) in several places. When you summon the dragon steed, choose a damage type listed in its inner dragon trait. You can determine the cosmetic characteristics of the dragon such as its color, scale texture, or any visible effect of its inner dragon; your choice has no effect on its game statistics.

In combat, the dragon shares your initiative count, but it takes its turn immediately before yours. It can move and use its reaction and bonus action on its own, but if it takes any action other than the dodge action, you must forgo your bonus action on your turn. That action can be one in its stat block or some other action. If you are incapacitated, the drake can take any action of its choice. not just Dodge.

You can summon the dragon a number of times per long rest equal to 1 + half your proficiency bonus, rounded up

The dragon remains for a number of hours equal to your proficiency bonus, until it is reduced to 0 hit points, until you use this feature to summon the drake again, or until you die. Anything the drake was wearing or carrying is left behind when the drake vanishes.

You can use the dragon steed as a mount as long as it is your size category or larger, regardless of what your size would normally allow.

Whenever you manifest your dragon steed, choose the one of the following fighting specialties. The dragon steed gains the benefits of the specialty until you summon it again, at which point you may choose the same specialty or a different one.

Defense. The dragon steed gains a +1 bonus to AC.

Charger. The dragon steed’s speed increases by 10.

Savage. When the dragon steed rolls  a 1 or 2 on a damage die for an attack, it can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. 

Opportunist. The dragon steed gains advantage on opportunity attacks.

Dragon steed

Medium dragon

Armor Class: 12 + PB

Hit Points: 6 + six times your fighter level (the drake has a number of hit dice [d12s] equal to your fighter level)

Speed: 35ft

STR: 17 (+3)

DEX: 10 (0)

CON: 17 (+3)

INT: 8 (-1)

WIS: 12 (+1)

CHA: 12 (+1)

Saving throws: Str +3 +PB, Con +3 +PB

Damage resistances: determined by the dragon’s inner dragon trait

Senses: Darkvision 60 feet, passive perception 11

Languages: Draconic

Challenge: Proficiency Bonus (PB) equals your bonus

Trampling charge. If the dragon moves at least 20 ft. straight toward a creature and then hits it with a bite attack on the same turn, that target must succeed on a DC 8+PB+3 Strength saving throw or be knocked prone. If the target is prone, the dragon can make another attack with its bite against it as a bonus action.

Draconic mending. When the dragon’s rider uses their second wind feature, both the dragon and it’s rider regain hit points equal to the rider’s proficiency bonus.

Inner dragon. When you summon the dragon, choose a damage type: acid, cold, fire, lightning, or poison. The chosen type determines the drake’s damage resistance.

Actions

Bite: Melee Weapon Attack: +3 plus PB to hit, reach 5 ft., one target. Hit: 1d4 plus PB piercing damage

Fight as one

Starting at 7th level, you have learned to fight more effectively with your dragon. You have advantage on saving throws made to avoid falling off your dragon steed. Additionally, If you fall off of it and descend no more than 10 feet, you can land on your feet if you’re not incapacitated.  Mounting or dismounting your dragon steed costs you only 5 feet of movement, rather than half your speed, you have resistance to the type chosen for your dragon steed’s inner dragon trait, and when within 30 feet of it, you can deal that damage type with your weapon attacks. You must declare you are doing so before you make the attack roll.

Fang and blade

At 10th level, you and your steed have both learned to fight in tandem with a barrage of strikes. You and your dragon both gain benefits from this.

Fang. Your dragon steed can attack twice, instead of once, whenever it takes the Attack action on its turn.

Blade. When another creature within 5 feet of you hits a hostile creature with a melee weapon attack, you can make an attack against the creature that they hit as a bonus action.

Soul of draconic fury

At 15th level, your dragon is a true manifestation of the fury that burns within you. Your dragon steed becomes large and gains a flying speed of 80 feet, and also becomes immune to bludgeoning, piercing, and slashing damage from nonmagical attacks, as physical attacks can no longer damage it’s essence.

Dragon strike

At 18th level, you and your dragon have attained a level of connection that allows each to benefit from the other’s offensives. When you or your dragon hits a creature with a melee weapon attack, the other has advantage on their next melee weapon attack against that creature before the end of their next turn.