Dark Rider

I thought the sun set rather early that evening. It felt like in times before when out hunting, the orange hues were a mark to begin home. but before I knew it, all I could see is darkness... That's when I heard it. The sounds of hooves, as clear as day in that dark night. But there wasn't the rattle of mail like a town guard out might have. A dead silence in the dark. Before I could even hide myself in terror, the night subsided, and it was once again sunset. Woe be to whatever that endless night marched for.

Dark Rider Magic

Starting at 3rd level, you learn an additional spell when you reach certain levels in this class. Limited in magical scope, the only two spells available are find steed and phantasmal steed, both of which you learn when you take this subclass. 

When casting either of those spells, you must cast it as a ritual with a casting time of 50 minutes (not including the ritual casting additional time). When cast this way the creature becomes your bonded mount; if you bind to a second, the first connection ends. The creature has no hit points (cannot share or take damage or effects for another creature), cannot attack, and cannot be killed. However, it can use and attune to items, and it can count as a mount for all other purposes. You share a bond with your beast, allowing you to see through it's perceptions as long as you are on the same plane of existence.

Endwalker

At 3rd level, you master the use of a mount in battle. Any mount you ride has their jump distance tripled. In addition, your mount takes any falling damage you would take while riding. If you make a melee weapon attack while falling, you may add one additional die of damage onto that weapon attack for every 10ft you fall. The maximum amount of dice you can roll with this ability is equal to half your proficiency bonus, rounded down.

Moon Sight

At 3rd level, your mount gains 150ft of darkvision, allowing it to act as your guiding eyes.

You and your mount are also adept at evading creatures that rely solely on their sight. While in dim light, you have advantage on checks and saves that rely on sight (such as a spell that requires sight to use)

Yami Strike

By 7th level, you learn a technique to strike a creature's most vital spot; the eyes. When you make a melee attack roll against a creature that has a special form of vision (except blindsight), you may take a -4 to hit on your attack. On a successful hit, you deal an additional die of necrotic damage, and the creature loses those forms of special vision until the end of your next turn.

Darkmist

At 11th level, you emit an aura of constant dark mist in a 15ft radius around you. Inside of that area is dim light. Creatures within that dim light that do not have darkvision that attempt to make an attack roll against a creature do not choose the target of their roll; you do (cannot attack self, objects, or the creations of spells or magical effects. Can only target a creature. This includes creatures summoned by spells). The target must still be within the reach of the attack.

Umbral Evasion

Starting at 15th level, you can manipulate your dark mist to fool and confuse foes. Whenever a creature would force you to make a strength or constitution saving throw, you can swiftly dash to the side, using your mist as a shroud to veil your true position; you may use your reaction to move up to you mount's movement, leaving your dark mist behind in it's same position until the beginning of your next turn, potentially causing the effect to miss you entirely if you are outside it's effective area or range. While you are moving in this way, creatures who did not see you before using this ability still do not see you during your movement