This is pretty much a custom class at this point.
The Bulk of this class is taken from the ranger and its drake warden subclass.

Hit Points

• Hit Dice: 1d10 per ranger level
• Hit Points at 1st Level: 10 + your Constitution modifier
• Hit Points at Higher Levels: 1d10 (or 6) + your Constitution modifier per ranger level after 1st

Proficiencies

• Armor: Light armor, medium armor, shields
• Weapons: Simple weapons, martial weapons
• Tools: None
• Saving Throws: Strength, Dexterity
• Skills: Athletics, Perception, Survival

Equipment
You start with the following equipment, in addition to the equipment granted by your background:

• (a) scale mail or (b) leather armor
• (a) two shortswords or (b) two simple melee weapons
• (a) a dungeoneer's pack or (b) an explorer's pack

A longbow and a quiver of 20 arrows

Favoured Enemy
Beginning at 1st level, you have significant experience studying, tracking, hunting, and even talking to a certain type of enemy.

Choose a type of favored enemy: aberrations, beasts, celestials, constructs, dragons, elementals, fey, fiends, giants, monstrosities, oozes, plants, or undead. Alternatively, you can select two races of humanoid (such as gnolls and orcs) as favored enemies.

• (Giants) You have advantage on Wisdom (Survival) checks to track your favored enemies, as well as on Intelligence checks to recall information about them.

When you gain this feature, you also learn one language of your choice that is spoken by your favored enemies, if they speak one at all.

You choose one additional favored enemy, as well as an associated language, at 6th and 14th level. As you gain levels, your choices should reflect the types of monsters you have encountered on your adventures.

Deft Explorer (Optional)
This 1st-level feature replaces the Natural Explorer feature. You gain no benefit from the replaced feature and don't qualify for anything in the game that requires it.

You are an unsurpassed explorer and survivor, both in the wilderness and in dealing with others on your travels. You gain the Canny benefit below, and you gain an additional benefit when you reach 6th level and 10th level in this class.

• Canny (1st Level)
  • Choose one of your skill proficiencies. Your proficiency bonus is doubled for any ability check you make using the chosen skill.
  • You can also speak, read, and write 2 additional languages of your choice.

Draconic Tounge
You can speak, read, and write Draconic. Additionally, whenever you make a Charisma check when interacting with dragons, your proficiency bonus is doubled if it applies to the check.

Draconic Resilience
As magic flows through your body, it causes physical traits of your dragon ancestors to emerge. At 1st level, your hit point maximum increases by 1 and increases by 1 again whenever you gain a level in this class.

Additionally, Your scales become more sturdy and glisten with faint elemental energy. When you aren't wearing armor Increase your AC by 1

Fighting Style
At 2nd level, you adopt a particular style of fighting as your specialty. Choose one of the following options. You can't take a Fighting Style option more than once, even if you later get to choose again.

• Druidic Warrior You learn two cantrips of your choice from the Druid spell list. They count as ranger spells for you, and Wisdom is your spellcasting ability for them. Whenever you gain a level in this class, you can replace one of these cantrips with another cantrip from the Druid spell list.

Primeval Awareness
Beginning at 3rd level, you can use your action and expend one ranger spell slot to focus your awareness on the region around you. For 1 minute per level of the spell slot you expend, you can sense whether the following types of creatures are present within 1 mile of you (or within up to 6 miles if you are in your favored terrain): aberrations, celestials, dragons, elementals, fey, fiends, and undead. This feature doesn’t reveal the creatures’ location or number.

Drake-warden Origin

Draconic Gift
At 3rd-level your transformation has taken hold and your mind has started to accept your new way of life giving you a deeper connection to dragon kind, granting you understanding and empowering your presence.
You gain the following benefits

• If you can’t already, you learn to speak, read, and write Draconic.
• You learn the thaumaturgy cantrip, which is a ranger spell for you.

True Dragon Form
Starting at 3rd level, you can use your action to assume the shape of a true Dragon that you have ancestry with. You can use this feature twice. You regain expended uses when you finish a short or long rest.
choose a damage type listed in its Draconic Essence trait. You can determine the cosmetic characteristics of your Dragon Form such as its color, scale texture, or any visible effect of its Draconic Essence; your choice has no effect on its game statistics.

• Draconic Essence
  
  • When you transform choose a damage type: acid, cold, fire, lightning, or poison.
    The chosen type determines your damage resistance, the damage of your bite, Breath Weapon and the damage of your Infused Strikes.

Your Ranger level determines how much like a Dragon you can transform to while still being in control of your body, as shown in the Dragon form table. At 3rd level, for example, you can transform into a Dragon but are unable to fly and your breath weapon is underdeveloped.

Dragon Shapes

You can stay in a Dragon shape for a number of hours equal to half your Ranger level (rounded down). You then revert to your normal form unless you expend another use of this feature. You can revert to your normal form earlier by using a bonus action on your turn. You automatically revert if you fall unconscious, drop to 0 hit points, or die.

While you are transformed, the following rules apply:

• Your game statistics are replaced by the statistics of the Dragon detailed bellow, but you retain your alignment, personality, and Intelligence, Wisdom, and Charisma scores. You also retain all of your skill and saving throw proficiencies, in addition to gaining those of the creature. If the Dragon Form has the same proficiency as you and the bonus in its stat block is higher than yours, use the Dragon Form's bonus instead of yours. If the creature has any legendary or lair actions, you can't use them.
• When you transform, you assume the Dragon's hit points and Hit Dice. When you revert to your normal form, you return to the number of hit points you had before you transformed. However, if you revert as a result of dropping to 0 hit points, any excess damage carries over to your normal form, For example, if you take 10 damage in Dragon form and have only 1 hit point left, you revert and take 9 damage. As long as the excess damage doesn't reduce your normal form to 0 hit points, you aren't knocked unconscious.
• Your ability to speak or take any action that requires hands is limited to the capabilities of your Dragon form. Transforming doesn't break your concentration on a spell you've already cast, or prevent you from taking actions that are part of a spell, such as Call Lightning, that you've already cast.
• You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so. However, you can't use any of your special senses, such as darkvision, unless your new form also has that sense.
• You choose whether your equipment falls to the ground in your space, merges into your new form, or is worn by it. Worn equipment functions as normal, but the DM decides whether it is practical for the new form to wear a piece of equipment, based on the creature's shape and size. Your equipment doesn't change size or shape to match the new form, and any equipment that the new form can't wear must either fall to the ground or merge with it. Equipment that merges with the form has no effect until you leave the form.

Draconic Gift At 3rd level, the bond you share with your drake creates a connection to dragonkind, granting you understanding and empowering your presence.

You gain the following benefits:

Thaumaturgy. You learn the Thaumaturgy cantrip, which is a ranger spell for you. Tongue of Dragons. You learn to speak, read, and write Draconic or one other language of your choice.

Feat or ability score

Extra Attack
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.

• Roving (6th Level)
  • Your walking speed increases by 5, and you gain a climbing speed and a swimming speed equal to your walking speed.

Elemental Affinity
Starting at 6th level, when you cast a spell that deals damage of the type associated with your draconic ancestry, add your Charisma modifier to one damage roll of that spell. At the same time, you gain resistance to that damage type for 1 hour.

Scale and Blood
At 7th-level the draconic heritage within you intensifies, protecting you and stoking your fury.

While in your dragon form , you gain the following benefits:

• You gain immunity to the damage type chosen for your Draconic Essence.
• Your Dragon form gains a swimming speed of 40 feet and can breathe both air and water
• Your bite attack available while in dragon form deals an extra 1d6 damage of the type chosen for its Draconic Essence and gains the benefits of the bonus stats seen in the Dragon form table to its damage.

Feat: All Natual Source: Homebrew
Prerequiset: Level 8 or Higher
You have honed your claws, sharpened your teeth, strenghtend your tail and so have become more damgerous when using your natual weapons.

• Your natual weapon melee attacks gain a +2 to Hit and Damage
• Your regular weapons can no longer benifit from your proficency bonus

Land's Stride
Starting at 8th level, moving through nonmagical difficult terrain costs you no extra movement. You can also pass through nonmagical plants without being slowed by them and without taking damage from them if they have thorns, spines, or a similar hazard.
In addition, you have advantage on saving throws against plants that are magically created or manipulated to impede movement, such those created by the Entangle spell.

Overchannel
Starting at 10th level, you can increase the power of your simpler spells. When you cast a spell of 1st through 5th level that deals damage, you can deal maximum damage with that spell.

You can use this feature a number of times equal to half your proficiency bonus (Min 1) with no negative effects. If you use this feature again before you finish a long rest, you take 2d12 necrotic damage for each level of the spell, immediately after you cast it. Each time you use this feature again before finishing a long rest, the necrotic damage per spell level increases by 1d12. This damage ignores resistance and immunity.

Tireless (10th Level)

• As an action, you can give yourself a number of temporary hit points equal to 1d8 + your Wisdom modifier (minimum of 1 temporary hit point). You can use this action a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.
• In addition, whenever you finish a short rest, your exhaustion level, if any, is decreased by 1.

Dragon's Breath
When you reach 11th-level, when not in your Dragon form you are able to use your dragon form's breath weapon.
as an action, you can exhale a 30-foot cone of damaging elemental energy Choose acid, cold, fire, lightning, or poison damage. Each creature in the cone must make a Dexterity saving throw against your spell save DC, taking 6d6 damage on a failed save, or half as much damage on a successful one.
This damage increases to 8d6 when you reach 15th level in this class

While in your Dragon form you may use this skill to change your breath weapon attack to any damage type avalible in your draconic essence table. The damage ammount is unaffected.

Once you use either of these features, you can’t use either of them again until you finish a long rest, unless you expend a spell slot of 3rd level or higher to use it again.

Ability Score or Feat

Dragon Wings [0] Source: Player's Handbook ¹⁾
At 13th level, Your affinity with dragons has reached its magnum opus as a paid of wings sprout from your back. If you already have wings then they strengthen becoming stronger and faster.
You gain a flying speed equal to your current speed, If you already have a flying speed and its less than your walking speed your flying speed increases to match your walking speed +20ft.
You can fly with your wings while wearing light or medium armor.
Clothing or armor not made specially to accommodate your wings cannot be worn.

Blazing Revival
At 14th level, the bond with your draconic heritage can save you from death. If you are reduced to 0 hit points and thereby fall unconscious, you can can instead regain half your hit points and immediately rise to your feet. casuing an explotion of elemental energy centered on yourself.
Creatures in 20ft of yourself must make a Dexterity saving throw (DC=00) On a failed save they suffer 4D10 damage and a thrown back 30ft, Knocking them prone. if they succeed the are pushed back half as much and only take half damage, not being knocked prone.
the damage type matches the one you chose for your heritage

Once you use this feature, you can't use it again until you finish a long rest.

Perfected Heritage
At 15th-level you have embraced your draconic blood nature and soul, you are Dragon.

You gain the following benifits:

• You can stay in your dragon form for an unlimited amount of time but the same restrictions apply
  • if you are reduced to 0 hit points or fall unconscious you revert to your normal self
  • You cannot change your Draconic essence or your apperance without first ending your dragon transformation
  • You still can only use this skill a number of times equal to…
• While in Dragon form all your attacks benefit from the bonus stat seen in the dragon form table to their damage
• a number of times equal to your proficency bonus you can chose deal and extra 2d6 of any damage type available (Cold, Lightning etc) in your Draconic essence when you perform any attack while in Dragon form.
  
• When you take damage in your Dragon form you can use your reaction to give yourself resistance to that instance of damage.

Feat

Feral Senses
At 17th level, you gain preternatural senses that help you fight creatures you can't see. When you attack a creature you can't see, your inability to see it doesn't impose disadvantage on your attack rolls against it.

You are also aware of the location of any invisible creature within 30 feet of you, provided that the creature isn't hidden from you and you aren't blinded or deafened.

Foe Slayer
At 18th level, you become an unparalleled hunter of your enemies. Once on each of your turns, you can add your Wisdom modifier to the attack roll or the damage roll of an attack you make against one of your favored enemies. You can choose to use this feature before or after the roll, but before any effects of the roll are applied.