Zetsuei is the name of Ryuho's Alter, named after his late Doberman that was used as material to first form it.
When the Crystallized embodiment of Alter energy showed up and attacked Ryuho, his mother and his dog, Zetsuei, it killed his mother and dog. The anger over this loss causes his Alter power to be unleashed. His dog atomizes and in its place was the humanoid being that would follow him for the rest of his life: Zetsuei, named after his now-late Doberman.
Stage 1: At this stage, Zetsuei in its "sealed" form appears as a black-and-white, humanoid figure, with its arms bound together in a crossed position by the tight cloth around its shoulders. Around its face is a large, metal plate, usually obscuring half of its face. There are a pair of purple, metal hinges around Zetsuei's waist, while the purple boundaries around the cloth extend outwards from Zetsuei's body to form two purple, razor-sharp, ribbon-like appendages that can stretch to any length desired and cut like blades. Zetsuei typically manipulates the structure of the ribbon tips to form sharp spear-heads to maximize potency against individuals. In the manga the number of ribbons it can generate are well into the tens in quantity.
Stage 2: The true manifestation of Ryuho's Alter. As referenced before, "Stage 1" is actually a suppression of the Alter's original power; when Ryuho decides to release its seal, it reverts back into this form. Its form changes to resemble a lamia (or a naga to be accurate), with greatly increased speed and power. This stage also has two rocket arms, and two regular arms.
Standing well above Ryuho himself in height, Zetsuei's "Stage 2" has a physical appearance not unlike that of a nāga: a vaguely humanoid head and torso, with a lack of legs and a serpentine form from the waist downwards (the upper and lower halves of Zetsuei are separate, but close enough to give the impression that it is whole). The black-and-white "bodysuit" of the sealed form has disappeared and is replaced by a distinctly, mechanical structure, with a curious, large eye in its chest region (a deep, green pupil in a yellow sclera) and purple metal extensions jutting out of its shoulders and its waist. A pair of detachable rocket-like appendages are attached to the upper arms, facing downwards and towards the back. The pair of ribbon-based appendages are still retained for Stage 2 Zetsuei, with their location now extending from around Zetsuei's head.
Stage 2 AttacksEdit
◾Vigorous Right Fist: Crouching Dragon (Genki Migi Ken: Fukuryu): The rocket-limb on the right-hand side detaches itself from the body and flies straight towards the opponent, colliding and delivering a powerful strike on impact.
◾Vigorous Left Fist: Bowing Dragon (Genki Hidari Ken: Garyu): Effectively the same as Vigorous Right Fist: Crouching Dragon, except now rendered as taking place on the left side.
◾Raitsujin: Stage 2 twists its two ribbons together into an enlongated spear, boosting their offensive power even further. Its name is only mentioned once in the series finale. A fifth attack, possibly the same as Raitsujin, is used in Episode 13.
◾Buzzsaw Tail: Stage 2 opens the end of its tail and spins it like a propeller, which allows it to function similar to a buzzsaw; this buzzsaw may be versatile, as it can be used to cut through opponents and objects, and may even be used to propell it, likewise a stylized propeller.
◾Rocket Punch: In the manga, Zetsuei possesses a rocket punch, with the ability to physically manipulate the position and angle of its rockets before firing them. It appears that an almost spatial effect is responsible for the incredible power of the rockets.
Stage 3: Fighting Dragon Bullet (Toryudan): In the third and final stage, Zetsuei becomes a harmonic, or s-CRY-ed, Alter, just like Kazuma's Shell Bullet, meaning it forms on Ryuho's body. Stage 3 appears in the form of extremely pointed and sharp metallic armor, deep purple in color, that is mostly reinforced around the head, shoulders and chest regions, but also extends across the limbs. In this form, Ryuho and Zetsuei are nearly as fast as the speed of light. The weapons for this stage are Ryuho's fists, which are given incredible cutting power, strong enough that a swing of one of his swords can easily cut multiple air jets and even battleships at longer distances. The shoulder-spikes are also detachable, and can be re-arranged together to form special wristblades for Ryuho. He can release invisible slashes of air pressure from the weapons, and the force generated by Ryuho's swings are sufficient to slice through even large Alter bomber aircraft and aircraft carriers. These diamond-shaped swords are powerful enough to cut the fabric of space, allowing him to theoretically bypass conventional defensive methods to strike a multitude of opponents. The resulting tear can extend for up to several kilometers in horizontal length (up and down, vice versa).