It's expected that when you're accepted as a member of the Green Lantern Corps, that you will not abuse your power and only use it for good. Unfortunately this wasn't something that Sinestro oblige with, leading to the supervillain being banished from the team, founding the Sinestro Corps and thus, becoming Hal Jordan's arch nemesis.

Here we have Sinestro in his White Lantern suit, armed with his sword and comes complete with a display base to give the impression he's floating in the air.