Path of the Black Dragon Knight

There exist myriad fighting styles, each of which has its own unique qualities. None, however, can claim to be as offensively minded as ours. Our approach is ever one of attack, no matter who─or what─we face. An experienced knight is able to wield a polearm as if it were an extension of his body. He transforms into a raging storm before his foes, delivering a barrage of devastating thrusts and slashes. In order to facilitate such a relentless offense, we favor armor of unique design, as provide adequate protection without sacrificing mobility. The measure of a lancer's worth is truly quite simple: how swiftly and decisively he can pierce the enemy's defenses.

Black Dragon's Power (Level 3)

When you choose this path, you learn to fight in the traditional Dragonslaying Style. Offensively, this comes in two forms: Skypiercer and Wing-Render. 

Skypiercer: You cannot gain a flight or hover speed. Instead, any flight speed you gained is shifted to your high jump distance, not counting against movement expended. While falling, you can take attacks or other actions while plummeting, such as making the attack action whilst falling. At 10th level, if you hit an attack whilst falling, that attack's damage reduces any falling damage you would take that turn by that amount. 

Wing-Render: Once per turn, while you are raging, you may make a special jumping attack against a creature you can see that is within distance to jump to, using a glaive or halberd. This attack can do either slashing or piercing damage, and deals an additional 1d12 acid damage on a hit. At 10th level, you can use this feature twice per turn.

 

Dragon Killer (Level 3)

You have learned techniques to destroy beasts and dragons of the skies; if you have a magical property that deals additional damage to dragons, you may add your barbarian level to that damage. In addition, you learn a technique to steep your weapons in the blood of dragons. This ritual involves slaying a hostile dragon, and stabbing your polearm of choice into the creature's body, soaking it in it's blood. The weapon stays soaked this way for one hour. Then, while soaked, you must be struck with a fire damage dealing breath weapon while holding the weapon. This tempers it, searing the blood into the blade. While you hold such a weapon, any time you roll a 20 to hit with that weapon, the creature takes 10d6 acid damage, and you gain temporary hit points equal to the amount done. 

Dark Scales (Level 6)

When you enter your rage rage, you clad yourself in a coat of black, iron like scales. If you are attuned to a set of heavy armor, you gain the magical effects of that armor, without being counted as armored. In addition, for the duration of this rage, you have resistance to acid damage, and to the damage from the breath weapons of dragons. 

You can also expend a rage as a bonus action to inspire fear in your enemies. For the next minute, you may take some form of intimidating or dramatic pose, adding 1d12 to any performance or intimidation checks to rally allies or rattle foes. If you make such a check just before combat begins, or on your first turn of combat, all hostile creatures of your choice that you can see becomes Rattled during the first round of combat, unless they have a passive insight greater than your check. While Rattled, their movement speed is halved, they have disadvantage on ability checks, and attack rolls have advantage against them. 

Geirskogul (Level 10)

As a bonus action after you take the attack action, you may make a mighty charge known as Geirskogul. You move 30ft feet in a straight line on the ground (expending that movement), hitting all creatures in a 5ft wide line. They must make a strength saving throw (DC 10+prof+str), or take 8d12 slashing damage plus 4d12 acid damage (Half on a success).

At 16th level, Geirskogul can be activated while falling to slam into the ground, then bursting forth with even greater  linear speed (on the ground). You can expend up to 3 additional instances of 30ft of speed, applying the saving throw and damage of Geirskogul for each time you expend it.

Eye of the Dragon (Level 14)

While raging, your eyes take on a draconic, slitted quality. You gain 10ft of truesight. Whenever you damage a creature with Geirskogul or your ritual weapon within the range of that truesight, they gain a stack of Dragon's Eye for a minute. When a creature has more stacks of dragon's eye than it's constitution modifier during your turn (No action required), you may expend them to unleash Stardiver. You call upon a star from the heavens themselves, causing a mote of radiant energy to float down to a point in the air you can see within 100ft of you. You can speak a command word to have that mote roar out, as if a breath attack from a dragon covering a 100ft cone beneath it. Creatures with at least 1 dragon's eye within the area must make a dexterity saving throw (DC 10+prof+str), or take d10s in radiant and acid damage (evenly split) equal to your barbarian level (Half on a success). If using this under a clearly visible starry night, it deals twice this amount of damage.