Inconvenient Convenience Store

It's inconvenient, but there's a convenience store that I keep wanting to go to! One day, a night shift worker who looked like a homeless(?) gangster(?) came into a small convenience store! Everyone is filled with anxiety because of his scary appearance, but gradually a fresh wind of change begins to blow through the convenience store. What is the identity of this mysterious nighttime worker who solves the long-standing worries and thirst of not only co-workers at the convenience store but also customers..?!