Katsuke

Katsuke was a skilled demon ninja and was a former comrade of Shinobi. They both were the original disciples for replacing their master, who founded the Demon Ninja Clan. Together they trained and fought off many evil demons who threatened their clan and taught their own disciples the art of demon and ninjitsu. However, as time went by, Katsuke began to grow jealous of their master over crediting Shinobi's skills and considered giving his powerful sword, the Shinsen, and the clan to Shinobi to lead as his successor. Enraged, Katsuke began to turn against the ninja clan and Shinobi by challenging them to battle. Katsuke killed their master and many ninjas in the process and even managed to wound Shinobi in the battle. However Shinobi managed to counter Katsuke's attacks and used the Shinsen to behead him and his corpse were burned to ashes in his grave. He was resurrected from the grave nearly a decade later by the Auditor, who manipulated and used him to go after Shinobi to claim his shards of the sacred orb in exchange for a second chance at life.

History
Around a decade before the events of the series began, Katsuke and Shinobi were the principal disciples of their founding master of the Demon Ninja Clan, the merciless and powerful race of demons training to be powerful ninjas. Katsuke himself proved to be a formidable ninja, training to his fullest potential to earn himself the position to lead the clan and possess his master's powerful sword, the Shinsen. Unfortunately for him, Shinobi too was also greatly recognized as a powerful demon ninja and presented more higher levels of skills to his master than Katsuke. After noticing that his master was crediting Shinobi and claiming that he should take his place as the new leader of the ninja clan and become the new wielder of the Shinsen, Katsuke began to feel betrayal inside him and decided to ultimately turn against his own clan as a result in order to surpass his master and Shinobi's power. He murders their master and kills many demon ninjas who defended against to Katsuke. A duel to the death was commenced between Shinobi and Katsuke, with Shinobi believing that Katsuke himself was consumed by feelings of hate, jealousy and greed. Katsuke attempts to mock Shinobi and merely overpowers and wounds him during the first moments of the duel, however Shinobi manages to counter Katsuke's attacks and beheads him with the Shinsen, killing him instantly. Shinobi, along with the remaining survivors of the ninja clan, take his body and burn it to ashes in his grave.

During the story
Nearly a decade after Katsuke's death, he is resurrected by the Auditor, who sensed his anger, hatred and greed within his corrupted soul. The Auditor manages to recreate an imitation body from Katsuke's ashes, mainly composed of clay and graveyard soil, therefore he could not feel any pain or blood seeping from his wounds even if he was struck physically by an attack. Imitation bodies, however, relied on some kind of source of energy in order to sustain their soul host, as they did not no longer belonged in the living world. In this case, Katsuke feeds on nothing but his past feelings from his previous life, only feasting on greed, anger and hatred inside of him.

One day, when Hank and Shinobi engaged into another argument, Shinobi was also struck with one of Katsuke's ninja stars after sensing that there was a strange presence among them. The reappearance of Katsuke shocked Shinobi and questions of how he is still alive after all the years have gone by. Katsuke sinisterly greets his old comrade and immediately engages in combat with the ninja while fighting with his two Dragon Swords. The battle was progressing with Katsuke taking over the fight, as Shinobi didn't know how to actually kill Katsuke with an imitation body, in which he felt no physical pain form Shinobi's attacks. The battle was halted when Hank interfered in the battle, using his Electro Fist on Katsuke, cracking a part of his body open without being able to repair it. A dark aura was escaping from the open crack and Katsuke attempted to cover it to prevent it from further draining. Knowing of Hank's true powers, Katsuke vanished into the shadows, leaving no trace for Hank or Shinobi to track him down.

Katsuke isn't seen again until he breaks into a small abandoned base camp where the Auditor was hiding. Slaying at least fifty of the Auditor's men in the process, he abruptly finds the Auditor and demands him to grant him more power in order to kill Hank and Shinobi. The unsurprised Auditor apologizes to Katsuke for the trouble after seeing his fatal wound. In return, the Auditor summons all fifty bodies that Katsuke has slain and enables Katsuke to absorb all of the corpses. With the bodies absorbed inside his body, Katsuke transforms into an abomination looking demon, who turns out to be far more dangerous than the former demon ninja himself. With this new power in hand, Katsuke sets off to find Shinobi and Hank's group, where he chases them up to a forest mountain cliff. Shinobi and Hank team up to fight against the enraged demon, who proved to outmatch both soldiers with his new powers. He was later killed by Hank using his Holo Wave since he recalled that he was able to use the technique against powerful demonic energy attacks. Weakened from his own attack, Katsuke lay on his back motionless. Shinobi pulls out a sacred Sutra and places it on Katsuke's head. As Katsuke dies one final time, and his imitation body begins to dissolve into the light, he finally sees that Shinobi should really be the one to carry on the demon ninja tradition, and finally rests in peace.

Personality
Katsuke had the mind of evil sealed within him after his death. He did not enjoy being manipulated by anyone and would use penalty of death if necessary. He usually mocks his opponents of their fighting capabilities and was merciless to those he despised most. Katsuke was also well known as a very cocky opponent who often enjoyed insulting his opponents to discourage themselves. His underestimation of his opponents were greatly mistook which ultimately resulted to his final downfall.

Physical Description
Katsuke resembles like most of the Demon Ninjas of his clan, except he wore black shades to cover his eyes and wore ninja wraps on his head which covered most of his face along with a traditional black ninjitsu uniform. In the beginning before he died for the first time he was seen wielding one katana blade. After he was resurrected he stole another katana blade from a fallen ninja and dual wielded them in battle.

Powers and Abilities

 * Speed Running: Shinobi's method of transportation. Whenever on the go, he is enveloped in a high speed run. Shinobi will also use this ability during battle to dodge his enemies attacks. This ability proves to be useful whether he needs to escape or use it in battle.
 * Strength: Shinobi has proven to scuffle with Hank, who is very strong, in mere fist fights. He was also able to tear a NEXUS agent's head from his body by tearing his spine and even was able to hold Hank's Buster Blade with little effort, despite being greatly hurt.
 * Shard Enhanced Abilities: Shinobi originally possessed three jewel shards: one in each leg and one in his right arm. These allowed him to run at exceptional speeds and increased the strength of his right arm. He eventually lost all three shards throughout the series, losing the first one from his arm in his first battle with Bellatrix.
 * Enhanced Stamina: Being a full fledged demon, Shinobi has incredible stamina. He states that he can run three days non-stop and he can fight for a long time even when he is wounded beyond the extent of regular humans.
 * High Endurance: Being a Demon Ninja, Shinobi has enhanced endurance. Even when he is seriously wounded he can still fight. In the battle with Edgar and Renkotsu he defeated them even though his legs were badly injured. Further proof of his endurance is then the Auditor impales Shinobi in the legs and drags him into his own body. While trapped within the AUditor, his toxic gas that could melt forests and mountains failed to melt or even severely injure Shinobi himself.