The Green Lantern Corps is made up of selfless, heroic and valiant individuals who answer the call to fight evil via the power of their willpower. Among the Corps' ranks are some of the most level-headed and undaunted heroes in the galaxy - as well as Guy Gardner. The brusque and uncouth GLC member isn't always the nicest person, but he's far more than just a bad attitude and a worse haircut.
Source：https://www.cbr.com/green-lantern-guy-gardner-development-dc/
