Your constitution score increases by 2 and Strenght by 1

Due to being humanoid, the Hyrda tend to be towards no particular alignment. The best and the worst are found among them. 

Hydra are taller and heavier than humans, standing well over 6 feet tall and averaging almost 250 pounds. Your size is Medium.

The walking distance of the Hydra is 30ft. Swimming speed is 25ft.

The humanoid Hydra can Age to a 1000 years, compared to their orignal counterpart. 

The humanoid hydra was able to gain the ability to speak. The hydra understands Common, Deepspeech and Draconic. 

For each head that the hydra has it does 1D6 of damage. (For example: five heads, 5d6 damage) The DEX saving throw equals 8 + your Constitution modifier + your proficiency bonus. A creature takes damage on a failed save, and half as much damage on a successful one. Damge increases from Hydra heads.

When reaching certain levels, the hydra will receive an additional head. Levels 1 to 4, the hydra starts off with three heads. Upon reaching level 5, the hydrant gains two heads. Having a total of Five heads. 

The hydra has multiple heads. While it has more than one head, the hydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

While the hydra sleeps, at least one of its heads is awake.