Ranma 1/2. It’s from the same mangaka that made InuYasha.

Another hypothesis is bruxism (teeth grinding). Some people have it during the day, others (like me) have it during sleep. Stress and anxiety makes it worse. I only discovered I had it because people heard me biting my teeth against each other while asleep. I went to a dentist, she made me a mouth guard that I use every night before going to sleep, and the morning headaches stopped since then.