I Became Invincible After Killing the Tyrant by Touching My Head

The whole world thought that Su Jin was seeking death by marrying the tyrant Di Yuan, but they didn't know that she was bound to a head-touching and killing system - stroking Emperor Yuan's fried hair can unlock ancient mythical beasts such as unicorns and green dragons. It wasn't until the system popped up the ultimate mission: [Tame this system - the ancient ferocious beast: Emperor Yuan] that she realized that what she had been gathering was the tyrant's body.