Justin is a Stickman, and the prototype of the Number Captain. He is the Wannabe-Arch-Enemy of Captain 0 because he was supposed to become Captain 0. He has the power to blast lightning and fly. Every time he tried to kill 0 he was defeated somewhat easily, but sometime later, he decided enough was enough...
After that he plotted his revenge on the wiki. He attacked when the wiki hit the 2000 page milestone, but this time he was stronger and nearly killed Captain 0. He then used his new powers to fight the Undefeatables in their own domain. Soon a crazy unicorn named Bjorn saw it and called in his team, the Peggle Masters to come try to stop him. Justin thought that he could beat them easily, but he was wrong. The Masters, alongside numerous other great powers in the UnUniverse, combined their attacks, resulting in Justin's complete disintegration. Thing is, he had a backup.
Eventually, he was restored by Googolplex, and was asked to join the Satanist Empire. Flashing back to his fight with Bob Saget, though, he ran away, and joined the Legion of Captains as a means of forgiveness for the Legion. So far, he is the third stickman to join the Legion, after 2i and Vesta.