1. Drinks are produced in the factory and used to level up fighters.
2. Each drink has a different color, and when used to level up a fighter of the same color, they will provide additional experience and a greater chance to level up their abilities.
3. Assigning a fighter to the factory increases the efficiency of producing materials, including drinks (along with other bonuses based on the fighter), and also will tend to result in more drinks being produced of the same color as the fighter.