Dragon Pact

You have forged a pact with a creature of fearsome power, deep knowledge and understanding, (and unparalleled pride and charisma), an Ancient Dragon. This being's true objectives and motives are very dependent on its interests and alignment which vary depending on its nature, or rather, specie. The spectrum could easily go "Finding luxurious treasures to increase its wealth." and "Wreaking havoc upon the inferior." to "Protecting the weak and helping the poor." and "Banishing the evil from this realm.". Such creature can be any Dragon of an ancient age and of any color.

Draconic Arcanum

As you create a pact with The Dragon, you learn how to borrow its elemental powers to aid yourself in battle. At level 1 and whenever you level up you can choose to learn one additional spell, as well as, you can also learn any evocation spell from the wizard's list of spells when you are given the choice to.

Veil of Scales

Starting at 1st level, you can use your reaction to beg for your Patron's protection, summoning ghostly scales to cover your body (matching the ones of your Patron) and receiving its blessing. Until the start of your next turn, your AC becomes 18 + your Dex modifier and you gain advantage on saving throws during this period. You can use this feature a number of times equal to your charisma modifier (minimum of one) per long rest.

Elemental Catalyst

Once you reach 6th level, the powers that have been bestowed upon you grow to new heights. Whenever a foe takes damage, from your spells or cantrips, of the same type as your Patron's breath, the target must make a Constitution saving throw against your spell save DC or become affected by one of the following effects:

Ailment Chart

ELEMENTs	Ailments
Acid	The target becomes Decayed for 1d4+1 turns. A Decayed creature takes 1d6 necrotic damage whenever it walks 5ft.
Cold	The target becomes Chilled for 1d4+1 turns. A Chilled creature's movement is lowered by 10ft. and the creature has disadvantage on saving throws.
Fire	The target, and anyone within 5ft. of it, become Ablaze, taking 1d6 fire damage. (A creature can't be hit twice by this feature until the end of your turn).
Lightning	The target becomes Incapacitated until the end of your next turn. An incapacitated creature can't take actions or reactions.
Poison	The target becomes Poisoned for 1d4+1 turns. A poisoned creature has disadvantage on attack rolls and ability checks as well as it takes 1d4 poison damage.

At the start of an affected creature's turn,  the target can re-roll the save at the start of it's turn to end the effect early. (The creature can not roll before the damage and effects are applied).

Perfectly Shaped Servant

As you reach level 10, you are gifted by your patron a more "adequate" form, that of a Dragonborn (if you aren't one already). While in this form your AC becomes 13 + your Dex modifier, and, if you choose to do so, you can grow wings and a tail on your back. Your flight speed is the same as your current speed. As an action, you can shift (partially or fully) between these forms but you can only do so for a number of hours equal to half of the sum of your Charisma modifier + Warlock level (rounded up), per long rest. If you go beyond this time, you can keep this transformation, but at the cost of gaining 1 level of exhaustion per minute you decide to remain in this form. If your hp reaches 0, you also revert back to normal.

Draconian Presence

Starting at 14th level, as an action, you can summon a ghostly visage of your patron, right behind you, to wreak havoc on the battlefield. Whenever you use this feature you can choose between Draconic Breath or Draconian Roar.
Draconic Breath: You command the visage to breathe down on your foes.The breath attack is the same as your patron's, although the save DC used for this attack is your own Spell Save DC. This breath attack doesn't hit you.
Draconian Roar:You command the visage to unleash a mighty roar to assert its dominance. Any target that can hear you, within 120 feet of you, must succeed a Wisdom saving throw against your spell save DC or become frightened for a minute. Any affected creature within 10ft. of you is pushed away by an additional 10ft, and must succeed on a Constitution saving throw with a DC of 10 + your Charisma modifier or fall prone.
After that, the visage is dispelled and you can only use this feature again after a long rest.