From my artwork THE JUSTICE LEAGUE OF ANIME. I painted each of the seven characters there separately, and here you can get a better look at each of them.
Comment and +fav if you want, but make sure you check out and do the same for the original artwork. [link]
Here is the story of how this character joins the Justice League. Read them in order.
Having secretly saved the world on countless occasions, Goku's life had become shallow. He'd participate in martial arts tournaments, and was happy to throw the final match so that his friend Hercule could remain the champion, but he couldn't help thinking that something was wrong. He didn't want the glory, he just wanted everyone else to be happy. Yet, despite everything, it was as if the crowds had no real appreciation, no enthusiasm, and just didn't care anymore. He noticed that was happening everywhere, not just at the matches, but in every aspect of life. As he contemplated just what had happened to today's generation, a tall, mysterious figure wearing a long cape appeared behind him.
"These people do not know what you have done for this planet, Son Goku, but I do."
"You!? But you're..."
"Nor do they understand how much they need your help again. It's time for you to learn the truth."