Tokyo Revengers S01E22 - One for all

Two years ago, Manjiro learns that Kazutora is beefing with the motorcycle gang, the Black Dragons, and decides he'd fight them as well. But he wanted a valid sense of purpose to take on a motorcycle gang. Keisuke then suggests they make their own motorcycle gang. They want to create a gang where they can all put their lives down on the line for each other. Keisuke had been fighting all alone to protect the promise they made the day they created their gang and put their money together to buy a traffic safety charm.