Once there was a fierce warrior. People called him The Destroyer. He spent most of his time drinking, but when he didn't - he fought. He fought like no one else. He wasn't as quick or skilled with as sword as samurai, but he was a lot bigger and stronger than avarage man. He could pick up his enemies like children and throw them at each other.
When the emperor was killed and nation succumbed to chaos, he was the one to protect people from invaders, when no one else did. Even though he was feared by people, he became a hero.