A broken promise is a frequent and sad theme in anime and real life.
A broken promise is a vow that never comes true or a deal between two people or more is broken. A broken promise has several factors that can cause it.
Note: Put all franchises in alphabetical order.
Kakashi's promise to protect Rin has fail when she dies later on. For that day, Kakashi swore to protect his team mates with his life.
Gale Glory fails to come back home after promising his daughter ,Cattleya Glory, and his wife, Sakura Glory.