Black Dragon Master, Novice

Dragon Student. The Novice's bond with its dragon partner (and patron) gives it access to an expanded spell list and a young black dragon companion. The dragon partner can cast spells as an action in place of the Novice (using the Novice's spellcasting modifiers), use its Breath Weapon action in place of the Novice's action, or take the Multiattack action from its stat block using the Novice's bonus action. Three times per day, when the dragon partner makes a Bite attack, it can deal additional damage of its type or recover health points (its choice) equal to 1d6+11. It takes the dodge action if not given any commands, and if the Novice is incapacitated, it will take any action it deems necessary. The Novice has a swimming speed of 30 ft and can breath water. 

Dragon Pact. The Novice and its dragon partner share spell slots (which are recovered after a short rest), but all spells cast by your dragon partner become damage of its respective type. Whenever the dragon partner casts or uses a spell, it can add the Novice's Charisma bonus to one damage roll for that spell. It can also cast eldritch blast as a modified breath weapon (see actions). The Novice concentrates on any spell cast by it or the dragon partner that require concentration. Whenever the dragon partner casts or uses as a spell, it gains 5 temporary hit points. 

Dragon Warrior. The Novice can use its Charisma instead of Dexterity or Strength for its attack and damage rolls when using one-handed weapons. These weapons are considered a spellcasting focus. When it hits with an attack, it deals an additional acid damage with that weapon equal to its Charisma bonus. It can also add its Charisma bonus to any Intelligence ability check it makes. If the Novice makes a weapon attack while riding its dragon partner, the dragon partner can cast a cantrip as a bonus action, instead of an action.

Innate Spellcasting. The dragon partner’s innate spellcasting ability is Charisma (spell save DC 16). It can innately cast the following spells: 

3/day- melf's acid arrow

1/day each- vitriolic sphere, insect plague

Spellcasting. The Novice is a 11th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). The Novice has following warlock spells prepared:

(at will): booming blade, eldritch blast, mage hand, prestidigitation, armor of agathys, jump

at 5th level (3 slots): absorb elements, hex, shield, dragon's breath, flaming sphere, invisibility, counterspell, fireball, lightning bolt, dimension door, freedom of movement, wall of fire, bigby's hand, cone of cold, synaptic static

1/day- true seeing

Acid Breath (Eldritch Blast). The dragon partner exhales lightning in a 60-­foot line that is 10 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 21 (3d10+4) acid damage on a failed save, or half as much damage on a successful one.

Longsword. Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit: 9 (1d8+4) slashing damage + 4 acid damage.

Acid Breath (Recharge 5–6). The dragon exhales acid in a 30­-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 49 (11d8) acid damage on a failed save, or half as much damage on a successful one.