Bloodhunter Companion Wyvern

Every level this creature grows with the blood hunter and gains 1d12+2 hit points per level.

Baby Wyvern. Starting at level 3, the blood hunter is able to hatch a dragon egg by spilling magically infused blood over the egg. At this age, the wyvern is considered tiny.

 Juvenile Wyvern. By 5th level, the wyvern has grown to be a small size.

 Young Adult Wyvern. By 10th level, the wyvern has grown to medium size. A single small creature is able to ride it.

 Adult Wyvern. By 15th level, the wyvern has grown to a large size. Two medium creatures can ride it.

Baby

Bite. Melee Weapon Attack: +5 to hit, reach 0 ft., one creature. 1d6 + 4 piercing damage.

Juvenile 

Multiattack. The wyvern makes two attacks: one with its bite and one with its claws. 

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. 2d6 + 4 piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. 2d8 + 4 slashing damage.

 Young Adult

Multiattack. The wyvern makes two attacks: one with its bite and one with its claws. 

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. 4d6 + 4 piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. 4d8 + 4 slashing damage.

Blood Suck. Melee Weapon Attack: +5 to hit, reach 0 ft., one creature. 3d6 + 4 piercing damage. The target must make a DC 15 Constitution saving throw, taking 4d6 necrotic damage on a failed save, or half as much damage on a successful one. The Wyvern heals half of all damage taken from this attack. The creature is considered grappled.

 Adult

Multiattack. The wyvern makes three attacks: one with its bite and one with its claws. 

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one creature. 6d6 + 4 piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. 6d8 + 4 slashing damage.

Blood Suck. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. 4d6 + 4 piercing damage. The target must make a DC 15 Constitution saving throw, taking 4d6 necrotic damage on a failed save, or half as much damage on a successful one. The Wyvern heals half of all damage taken from this attack. The creature is considered grappled.