Tokai Natsui was working in an electronics firm when his uncle Cyber-One made the call for the ninja clan to reform. Natsui didn't even know that he was descended from ninja. The prospects of becoming a ninja thrilled the nerdy Natsui. Stealing as much of the electronics that he could, Natsui left the electronics company for the Darkpool ninja clan.

As a member of the clan, Natsui assisted in the creation of the Blue Steel ninja robots that Cyber-One was putting together. Natsui had dreams of the daring assassinations that he would perform, just like in the movies. However, over time, Natsui grew dissatisfied with the Darkpool. Sure he was an important Secret Whisper ninja, but they never killed anyone. All they ever did was still information, and the Blue Steel robots were just so much cannon fodder. To Natsui is was so disappointing. Then to make matters worse, Cyber-One introduced e-Space. Impotent rage filled Kage. e-Space was going to be Cyber-One's lieutenant. Natsui knew in his bones that he, Tokai Natsui, should have that place of honor, not some computer hacker like e-Space.

Natsui dropped out of sight for a while. It was while in hiding that he started the construction of his Kage Mushi or Shadowbug battlesuit. Natsui knewe that with his battlesuit, he would surely impress his uncle and disgrace the upstart e-Space. Natsui based his battlesuit on the Japanese beetle. The battlesuit even had wings that popped out of the back on command of the wearer. The cowardly e-Space wouldn't have a chance against Kage Mushi.

It was at meeting at a secret place in Tokyo that Kage Mushi struck. He knew that Cyber-One and e-Space both would be attending the meeting. Like a giant beetle, Kage Mushi flew into the room. In a loud altered voice, he callenged e-Space to a duel. The young man seemed to be taken aback. He was an information junkie, and hated to fight. However, Cyber-One saved him from losing face by taking on Kage Mushi himself.

This wasn't what Natsui had planned. Smiling Cyber-One bowed slightly to his opponent, who opened up with a concussion blast that tore a section out of the wall. However, it missed the agile Cyber-One completely. Meanwhile, Cyber-One performed an acrobatic flip and landed a Sublime Fist of the Night Dragon on the chest of Kage Mushi. The impact was so great that he was thrown through three walls before crash landing in an alley. Cyber-One not letting Kage Mushi regain his feet came running out after him firing his Dance of the Six Stars at Kage Mushi. Shards of metal impacted with the alley way, Kage Mushi. Severely damaged, Kage Mushi was left for not other options. Jumping high into the sky he fled. Since that day the Darkpool have kept an eye out for the armored ninja. They still don't know who he is, but when they capture him, Cyber-One has vowed to tear him limb from limb.

With Japan being too dangerous for him, Natsui left for greener pastures. He has fixed his battlesuit, and has fallen in with Dirty Deeds. Kage Mushi primarily stays away from contracts that would take him back to Japan. He has no desire to confront his uncle again, but if he were to cross paths with e-Space, Kage Mushi would move Heaven and Earth to get revenge on him.

Natsui strives to be a great person, a person who's deserving of respect. It is, however, at times when the respect isn't forthcoming that his immaturity truely shows. He's confused why Cyber-One chose e-Space or him. This is the base of his dislike for e-Space. While he knows that his uncle would be angery with him for what he has done, he feels that he has an important place in Darkpool if it wasn't for e-Space.

If Natsui has a saving grace, it's his ability with machines. Natsui is constantly tinkering with machines. His Kage Mushi battlesuit is constantly evolving in minor ways. He's always on the look out for better technology, and watching for Darkpool ninjas.

"I will make my mark on the world. In the shadows of course."

Natsui wears a suit of armor of his own designing. The battlesuit is heavily armored, and has its' own builtin life support system. The exoskeleton enhances the wearers strength to superhuman levels. The speed of the wearer too is increased. Built into the back of the battleuit are four wings similiar to a dragonfly's. The wings allow the wearer to fly. Offensively, the suit has an energy concussion blaster built into the gauntlets.

In addition to the battlesuit, Natsui is able to construct a nano-bot swarm. Normally the swarm is completely invisible to the naked eye. Natsui can put the nano-bots into two different modes. The first mode is a surveillence mode, in which Natsui can see and hear in a large area around himself, and the second is an offensive mode, in where the nano-bots attack relentlessly.

Kage Mushi wears a battlesuit that looks similar to a Japanese beetle. The battlesuit completely covers the wearer from head to foot. The helmet of battlesuit is similar to a kabuto, with a demonic looking mempo. On the back of the battlesuit is a carapice which splits open reveiling four dragonfly like wings. Outside of the Kage Mushi battlesuit, Natsui is a sallow skinned Japanese man, who wears glasses. He's a nerd.