Super Saiyan 6 is a variation of the Super Saiyan forms. This form is one of the most powerful forms a Saiyan can obtain. While not being impossible to obtain, this is quite hard.
On a normal day, Leo was training on New Planet Vegeta. He powered into his final form of Super Saiyan 5, against his friend, Kyo. Kyo, is a fighter, who protected New Planet Vegeta from Cooler. Kyo was in Full-Power Super Saiyan 4. Leo mis balanced his Ki, like Xios, and formed into a Super Saiyan 6. Kyo was amazed at his appearence.