|“||In giving that monster refuge, your true power emerges. Excellent. I've been anxious to see what you're truly capable of. But you're not the only one who can transform. Now, accept your punishment!||„|
Deko Gekisho, or Deko, is the leader of the Nebulox and the main antagonist of Sin and Punishment: Star Successor.
As the leader of Nebulox, he and his squad was sent out to find and kill Isa and Kachi, since Isa had went rogue and Kachi was believed to be a threat to the universe. Isa and Kachi attempt to escape from the Nebulox, but their plans are constantly thwarted at every turn since the Nebulox are always watching and they seem to be everywhere. Eventually, Isa and Kachi decide to take the fight to the Nebulox themselves by attacking their base located at Earth's energy hub, Mount Fuji. Upon arriving at the base, Isa and Kachi are confronted by Deko, who sends out an army of soldiers to deal with the two. They manage to defeat the soldiers, and after defeating Deko in a gunfight, Deko activates the device that weakens Kachi, then challenges Isa to a one-on-one fistfight. Isa gets the upper hand on Deko and subdues him, then tends to Kachi. Deko later escapes as the base implodes, and Isa and Kachi later fuse and pursue the Nebulox into space for a final showdown. Isa attacks the Nebulox's battleship and kills the Nebulox leaders one by one before facing off against Deko again. Eventually, Isa manages to defeat Deko once and for all.