Which teenage character has died in real life of Harry Potter movie?

There seems to be some confusion in the question. You're asking about a teenage character from the Harry Potter movies who has died in real life.

It's important to remember that the Harry Potter actors are real people, but the characters they play are fictional. While some actors have sadly passed away since the movies were made, none of the teenage characters from the Harry Potter movies have died in real life.

Perhaps you're thinking of a specific actor? If you can provide more details, I might be able to help you.