Only the central head has a brain. It is very intelligent, but it thinks only of destruction.
It's said that Hydreigon grew ferocious because people in times long past loathed it, considering it to be evil incarnate and attacking it relentlessly.
Hydreigon is my FAVORITE POkemon! Partially because I love dragon tytypes, and also becaues my Grandpa was German, and I looooved learning the language when I was little! For context: Hydreigon is German if you didn't know!