Fortified Armor Shell Zero

Fortified Armor Shell Zero (強化外骨格 零, Kyōkagaikokkaku Zero"), or Zero Armor for short, is Kakugo Hagakure's designated Fortified Armor Shell. Made as part of Shiro Hagakure's Tactical Human Weapon program during WWII, Zero is a powered exoskeleton forged from the souls of 3,000 deceased warriors. It tried to kill Kakugo when he tried to put it on. However, it ultimately aids Kakugo in protecting humans against the Tactical Fiends, and later Harara and Kasumi.

Appearance
Zero is a spiked, sci-fi armored version of WWII Japanese fighter pilot uniforms. It has a black undersuit with shiny black-and-silver metallic armor (a dark-blue undersuit and black armor in the anime). The elbows and knees are covered by pads, and while each elbow pad has three silver screws, each kneepad bears four silver screws. The flesh-like internals of the suit are noted by Kakugo to feel like animal intestines. When the armor is equipped, metallic plates of armor and cords of high-polymer muscle fiber engulf Kakugo's body. Normally, Zero's helmet has a faceplate with a notable nose and nozzles for respiration tubes. However, when going into Assault Mode, the respiration nozzles open and generate spikes. The ear caps also folded out, generating spikes as well. Lastly, the armor has a large, trailing white scarf around its neck.

Specifications
Made from a special malleable titanium alloy that repels most attacks, Zero is capable of withstanding heat of 2,000°C and cold of minus 70°C. It's Heat-Proof, Cold-Proof, Bulletproof, and equipped with a life-support system around the waist which can keep the wearer alive for 40 days. The suit has polarized light filters for its eyes, several nozzles in its hands, small thruster jets on its back, and it has a chemical compound device on the left hip that can both create antidotes and generate the devastating Kamikaze Tactic chemical weapon.

Abilities
Zero comes with several abilities that aid Kakugo against his enemies:


 * Painless Anesthetic Liquid: Initially used against Hamuko, Zero can shoot anesthetic fluid from the chemical weapon nozzle in its left index finger. However, it only worked on her for a few seconds, due to her superhuman constitution.
 * Flamethrower: Zero can shoot a stream of flame from its right index finger. Kakugo used it to cremate Hamuko's victims.
 * Ultraviolet Wave: Zero can cover its arms (or even its whole body) in ultraviolet waves, allowing Kakugo to cut through steel.
 * Sulfuric Acid: Zero can shoot a stream of sulfuric acid from its right index finger.
 * Dehydration Powder: Zero can launch powder from the nozzles in its hands that dehydrate an enemy and turn them into ash.
 * Sublimation: Zero can launch a blast from its right hand that immediately destroys most foes with intense heat and pressure.
 * Scorching Heat: Zero can heat its exoskeleton. In addition to igniting the entire body, Zero can cover just one arm, allowing Kakugo to cut through materials with a chop.
 * Note: in the earlier chapters of the manga, this role was filled by the Ultraviolet Wave.
 * Acceleration Jet: Zero has small thruster jets on it back, the back of its legs, and its feet. These jets can be used to fly short distances. Kakugo and Zero mainly use them to quickly dodge enemy attacks.
 * Accelerated Decay: A technique using the Acceleration Jet, used against Megumi. After slamming her into the ground, Kakugo activates the Acceleration Jet and grinds Megumi into the ground.
 * Explosive Sudden Ejection: Zero's armor can be shot out and scattered in all directions, like a bomb. This is triggered by Kakugo to escape Rai's suicide attack.
 * Instant-Removal Armor Bullet: An autonomous version of the Explosive Sudden Ejection. Zero fires its parts in a shotgun-spread.
 * Unnamed mind scan: Zero can generate additional wiring and use it to read a person's brain.
 * Chemical Weapon - Divine Wind (Kamikaze) Tactic: After connecting the chemical compound device on the left hip to the left arm via a retractable cable, Zero can discharge an invisible vapor from its fingertips that instantly kills hundreds of Tactical Fiends.
 * Note: In the original manga, it's never explained what this vapor is. However, in Exoskull Zero, this is explained as a potent and deadly nerve gas.

Zero's Will
As noted before, Zero is forged from the souls of 3,000 deceased warriors. However, those vengeful souls form a collective consciousness within the armor. Symbolized by a myriad of human skulls, Zero's Will showed Kakugo the horrible history behind the armor's creation. When Kakugo showed the determination to wear the armor despite it giving him immense pain and suffering, as well as showing mercy, compassion, and understanding towards the vengeful souls, they recognized him as a worthy warrior and allowed him to wear the Zero Armor.

From then on, Zero's Will becomes a powerful ally, serving a function similar to a sentient A.I. from a mecha series. They alert Kakugo to threats both in and out of combat (although only he can hear them), give advice on how to defeat specific opponents, and can activate certain functions of the Zero Armor without Kakugo's direct commands, such as administering an antidote when Kakugo is poisoned. It can even fire off parts of the armor as projectiles to strike enemies from afar.

However, Zero's Will is very protective of Kakugo, going so far as to equip the armor for him should he be in immanent danger. They can feel insulted, like when Harara called Zero a prototype for Kasumi. They even feel a little jealous towards how Kakugo holds Horie after their return from the afterlife. While they do initially have to remind Kakugo to not get attached to any single person, they respect Kakugo as both a warrior and a human being.

Unfortunately, they also serve as the Zero Armor's greatest weakness. Upon being hit with the Light of Nivana from the sutra ball, Zero's will loses its hold in the physical plane. Without the will to guide it, the Zero Armor becomes dead weight, even unequipping itself from Kakugo. During a flashback, Zero is exposed to a similar attack from Kasumi's helmet, but Hail's intervention only renders Zero paralyzed.

Trivia
The armor resembles a red-eyed tokusatsu superhero with a long scarf similar to the Kamen Rider series.