Metamorpher

You have made a pack with a otherworldly being who takes pleasure in watching growth that has been touched with randomness. Observing what greatness can come of it when the transformations are dictated by a mortal being. They enjoy the shock of seeing what appears to be rare or normally chaotic creatures being tamed and ridden like a common horse among the populace. They've given you a shell of a beast that will grow with time to become a creature to be feared. The creature can range drastically from unicorns and nightmares to jaguars and winter wolves but only by appearance. This creature is ageless and can only truly be vanquished by the patron. After the Warlock has perished the creature returns to the realm of the patron where it's strange appearance will entertain them for however long it does.

Example: Dire Boars, Large Felines, Moon-Horse, Mastiff, Nic'Epona, Nightmare, Steeder, Unicorn, Winter Wolf, Worg. (Or something entirely new, up to DM.)

The creature does not inherently possess any of its natural abilities for example: (Blink Dog teleportation), attacks, resistances/immunities (Nightmare Fire damage immunity), or spells (Unicorn Innate Spellcasting).

Throughout your travels the choices you make modify the appearance of the creature, especially when you come to level 6 and 10. While the creature will never be the size of a dragon its it can still be quite imposing if desired or quite cute. For example, what started as a ordinary unicorn, unique in its own right, has taken the Flight Evolution option and now resembles a pegasus or has taken the Demonic Evolution option and now resembles a corrupted terror of a beast. Even a Nightmare's fiendish appearance can become something special after taking the Angelic Evolution option or maybe dip a bit further in that hell horse notion after taking the Flame-touched Evolution. Have fun!

Unity

Starting at 1st level, your patron bestows upon you the ability to summon a creature. This creature is your mount and its size becomes ride-able. It doesn't need to eat, sleep, or breath and it is unaffected by the weather. The creature can stay in this realm indefinitely so long as you are not considered perished.

Summoning the creature takes an action. Mounting the creature takes the entirely of your half movement per turn.

While mounted:

• You share AC, HP, and other stats with the creature.
• Either of you being attacked or being the target of a spell or ability is considered one target.
• You gain 15ft to your movement speed.
• You have advantage on saving throws made to avoid falling off the creature.

While not mounted:

• You do not share your AC, HP, and other stats with the creature
• Any bonuses provided while mounted is loss.
• The creature has a AC equal to half of yours.
• It takes its turn immediately after you but it can only take the Dodge action and uses its move to avoid danger and should it be hit during combat, before damage, it teleports from this realm.

The creature is an ally to you and tentatively to your companions. While you are mounted on the creature it will allow one other to ride with it. If you are not mounted it will not allow anyone else to mount it and will not move should someone else be on it. Similarly if you and another are mounted and combat begins it will not move unless that person dismounts. It understands one of your languages but cannot speak it.

Sync

At 1st level if mounted on the creature, after you use your action to attack a target in melee range, you may as your bonus action have your mount perform a melee attack. This attack adds your Proficiency Bonus to its chance to hit, reach of 5 feet, and deals 1d8 + your charisma modifier. The damage dice increase to 1d10 at level 6, and 1d12 at level 10.

 The type of damage is dependent on its source. For example: Beak (Piercing), Bite (Piercing), Claws (Slashing), Hooves (Bludgeoning), Horn (Piercing), Spikes (Piercing or Slashing), Tail (Bludgeoning).

Evolution

At 6th level you choose a damage type: Acid, cold, fire, lightning, psychic, necrotic, radiant, or thunder. You gain resistance to this type while mounted on the creature. Your Unity summon evolves in appearance to uniquely coincide with this decision and any further additions from Evolution.

Additionally once at level 6 and level 10 you pick from this list to modify your creature with one of the following:

Angelic: As a bonus action you may have all allies within 30 feet of you while your mounted have advantage on saving throws until the beginning of your next turn. You may do this once per short rest. Additionally while out of combat you can choose to have your creature sheds bright golden light in a 20-foot radius and dim light for an additional 20 feet. Entering combat removes this affect and it cannot be used again until combat is over. This Evolution cannot be taken if you took Demonic.
Armored Scales: The creature grows scales across its body replacing any fur or weaker scales already present. While mounted you get a +2 to AC as long as you're wearing light armor. Furthermore if you were to be hit by a second successful hit in a round that does bludgeoning, force, piercing, or slashing damage you treat that damage as being resistant to it. You can only do this once per round. This Evolution cannot be taken if you took Frenzied.

Ballad-touched: The damage from Sync is now considered thunder damage. Damage from Sync with this -touched Evolution can be used as a range attack, 20ft/60ft, and ignores close combat restrictions for ranged attacks. Additionally you may cast Shatter once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.

Death-touched: The damage from Sync is now considered necrotic damage. Additionally you may cast Vampiric Touch once without using a Warlock spell slot, and not needing it prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.
Demonic: As a bonus action you may have all enemies within 30 feet of you while your mounted have disadvantage on saving throws until the beginning of your next turn. You may do this once per short rest. Additionally while out of combat you can choose to have your mount have all lights weaken to a point of practical nonexistence in a 20-foot radius and become a weakened light source an additional 20 feet. Entering combat removes this affect and it cannot be used again until combat is over. This Evolution cannot be taken if you took Angelic.
Elongated: (Claws only) The creature claws become longer and more durable capable of climb and dig while mounted. You mount gains a climb speed of 15 feet and a burrow speed of 15.
Fearless Trot: While mounted you do not provoke attacks of opportunities. The mounted movement speed bonus increases by +10.

Flame-touched: The damage from Sync is now considered fire damage. Additionally you may cast Scorching Ray once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.
Flight: The creature sprouts wings capable flight while one person is mounted. The creature has a flight speed equal to your movement speed and can do so while you are mounted if you are wearing light armor and half that if wearing heavier armor.
Frenzied: The additions to your chance to hit from Sync becomes equal to your proficiency bonus plus 3 and the damage die becomes 2d10+ your charisma modifier. Furthermore you may choose to use the Sync attack as your action on your turn and again as a bonus action. The damage dice increase to 2d12 at level 10. This Evolution cannot be taken if you took Armored Scales.
Gills: While mounted you can breathe and see underwater. Furthermore the mount has a swim speed equal to your movement speed and can do so while you are mounted if you are wearing light armor and half that if wearing heavier armor.
Greener Pastures: While mounted and out of combat you spend one minute to create a one way portal, 12ft high and 6ft across, that lasts for lasts a minute or until you've gone through it. If it was the same plane of existence the portal shows the last visited farmland or grassland visited otherwise the portal fails. Traversing is instantaneous. You cannot use Greener Pastures again until after you finished a long rest. This is considered magical and can be counterspelled and dispelled. (The DC equals 10 + The Warlock's proficiency bonus)
Height Mastery: While mounted you ignore the close combat restrictions given to range attacks. Additionally after using your range attack you may use your bonus action for Sync against an acceptable target within the creature's range.

Holy-touched: The damage from Sync is now considered radiant damage. Additionally you may cast Moonbeam once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.

Mental-touched: The damage from Sync is now considered psychic damage. Damage from Sync with this -touched Evolution can be used as a range attack, 20ft/60ft, and ignores close combat restrictions for ranged attacks. Additionally you may cast Mind Spike once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.

Snow-touched: The damage from Sync is now considered cold damage. Additionally you may cast Hunger of Hadar once without using a Warlock spell slot and not needing the spell prepared. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.

Storm-touched: The damage from Sync is now considered lightning damage. Additionally you may cast Lightning Bolt once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.
Stabled: As a action you may choose yourself and up to 4 willing creatures who are within 30ft. They each regain hit points equal to 2d8 + your Charisma ability modifier. This has no effect on undead or constructs. The healing increases to 4d8 + your Charisma ability modifier at level 10. You may do this once per short rest. This is considered magical and can be counterspelled. (The DC equals 10 + The Warlock's proficiency bonus)
Stride: Your creature can now traverse without being affected by terrain and walk across bodies of liquid, including lava/magma. While mounted you are unaffected by nonmagical colds, heats, and poisons surrounding you. However anyone else on the creature does not benefit from this.

Vile-touched: The damage from Sync is now considered acid damage. Additionally you may cast Acid Arrow once without using a spell slot, and not needing the spell prepared, at its highest available level. You cannot cast this spell this way again until after a long rest. You may only have one -touched Evolution.

The Eldritch Rider

At 10th level at the beginning of your turn you may as an action use this ability while your mounted on the creature. It uses as much movement speed that would take you in a straight line but does not provoke attack of opportunities. Any enemy that is within 10ft of you during your movement must succeed on a DC 15 Wisdom saving throw or become frightened of you for one minute.

While it is frightened in this way, a creature must spend its turns trying to move as far away from you as it can, and it can't willingly move to a space within 30 feet of you. It also can't take reactions against you. For its action if you are the closest opponent to them, it can use only the Dash action or try to escape from an effect that prevents it from moving, otherwise it can use its action to attack anyone but you. If it has nowhere it can move, the creature can use the Dodge action. At the end of each of its turns, a creature can repeat the saving throw, ending the effect on itself on a success.

You may do this once per short rest.

Eldritch Charge

At level 14 should an enemy be knocked unconscious from an attack by you while you are mounted or by an attack from your creature you may immediately take another turn after this one is over though can only use that turn to use your movement and use your action and bonus action to perform melee or ranged non spell attacks from you and/or your mount. You can only take an extra turn once per long rest.