Blood Dragon

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Spellcasting. The Blood Dragon  is a 6th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 25, +16 to hit with spell attacks). The blood dragon has following Sorcerer spells prepared without needing any components:
Cantrips (at will): Firebolt, Mage Hand, Control Flames, Bonfire, Shocking Grasp.
1st level (4 slots): Chaos Bolt, Chromatic Orb, Shield, Ray of Sickness                    2nd level (3 slots): Mind Spike, Aganazzar's Scorcher, Phantasmal Force                        3rd  level (3 slots): Lighning Bolt, Fireball, Thunder Step

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: + 15 to hit, reach 15 ft., one target. Hit: 12 (2d10 + 7) slashing damage. 

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 7) piercing damage. 

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 21 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Fire Breath (Recharge 5-6). The dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 24 Dexterity saving throw, taking 91 (26d6) fire damage on a failed save, or half as much damage on a successful one.

• Detect. The dragon makes a Wisdom (Perception) check.
• Tail Attack. The dragon makes a tail attack.
• Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 ft. of the dragon must succeed on a DC 25 Dexterity saving throw or take 17 (2d6 + 10) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.