Hoshigetsu

Hoshigetsu (星月) is the spirit of Kichirō Getsueikirite's zanpakutō. He is the third "Getsuga-using Zanpakutō" next to Zangetsu and Engetsu. He is also known by his Bankai name, Kōken Hoshigetsu (月牙天衝).

Appearance
Hoshigetsu could easily be mistaken for Kichirō's twin. He is the same height and weight as Kichirō, and has Kichirō's hair style and hair color. He has golden-colored eyes and has his left eye covered by a mechanical eyepiece. The spirit of Hoshigetsu wears a blue top that covers only the top half of his body as well as a white coat that flares out into several "wing-like" appendages. He also wears long, blue jogging pants. In his Bankai, he looks slightly younger and wears a mask covering his eyes. He also has a scar like Kichirō's under his left eye. In this form, he wears a long white robe with a fur hood.

Personality
Hoshigetsu acts like a typical teenager. Careless, reckless, and incredibly arrogant which is starkly contrasted by his quiet, level-headed master. He detests when Kichirō's power is made fun of and will often grant him more power to kill whoever is mocking him. He does this because he views any mockery of Kichirō's power as mockery of his own power and therefore is very offended by it. Hoshigetsu is deeply afraid of Kichirō being sad and therefore offers him any type of power he can in order to quell that sadness. Overall, Hoshigetsu also seems to enjoy his master's company and will become sad or angry if Kichirō doesn't speak to him often.

As Kōken Hoshigetsu, however, his personality dramatically changes. He is now much more serious and is very concerned about protecting Kichirō at all costs. Kōken Hoshigetsu has a very aristocratic personality — acting completely apathetic to others even when he is troubled by something. Seldom is he ever surprised at any outcome. Even upon sensing Seireitou Kawahiru's enormous reiatsu, Kōken Hoshigetsu notes that it's only a mere fraction of his own power, though whether or not this is just a cocky statement has yet to be seen. He often states that he is bored whenever Kichirō fights, claiming he could fight much better. Later on, this is proven to be true, as Kōken Hoshigetsu is far above Kichirō's skill level.

Powers & Abilities
Master Swordsmanship Specialist: Hoshigetsu is a Zanpakutō, therefore he is extremely knowledgeable and skilled with a sword. When he and Kichirō first dueled to see if the latter was worthy of Shikai, Hoshigetsu clearly outmatched Kichirō in almost every way.

Spiritual Power: Hoshigetsu has the same spiritual signature as Kichirō, though whether he has as much spiritual energy as Kichirō has yet to be seen.


 * Getsuga Tenshō (月牙天衝, Moon Fang Heaven-Piercer): Raian speculates that Kichirō somehow inherited the Getsuga technique through Raian's soul link with Ichigo. Hoshigetsu himself, however, states that he is a "Getsuga-using Zanpakutō", much like Zangetsu and Engetsu. At the instant of the slash, Hoshigetsu absorbs his spiritual energy and releases highly condensed spiritual energy at the tip of the blade, magnifying the slash attack and then flies forward. This slash takes the form of a crescent moon or in the shape of a wave. As stated by Zangetsu, the second "Getsuga-using zanpakutō", knowing the name of an attack heightens its power compared to its strength when the wielder does not know its name. The Getsuga Tenshō is a powerful technique with great force, capable of causing large-scale damage and destruction. Hoshigetsu can use this technique in several different manners, such as striking the ground to create an omnidirectional blast to knock away incoming attacks or slashing at the ground to upturn it and crush everything in its path. Kōken Hoshigetsu retains Getsuga Tenshō, which can now be used from his finger blades. When used in Βankai, his Getsuga Tenshō is black with a red outline and their paths can be controlled through his hand gestures, making it easier to control than Zangetsu's own Getsuga. He can also keep these blasts within his finger blades to explosively increase the lethality of his punches and slices. Also, due to being able to fire them from his fingers, he can fire the Getsuga Tenshō much like an Arrancar does his Cero.
 * Ijō Getsuga (籠月牙, Caged Moon Fang): By swirling the spiritual energy of the Getsuga Tenshō, and then releasing it, Hoshigetsu can trap an opponent(s) in a massive dense sphere with a silver-green center. While inside, an opponent is incapable of physically escaping the spiritual stronghold, but a strong enough spiritual attack should be capable of destroying the sphere.


 * Getsuga Chirashi (散らし月牙, Scattering Moon Fang): Hoshigetsu is capable of scattering the Getsuga energy around himself as his opponent for multiple purposes. One, in order to cloak his appearance in battle and to hinder an opponent's eyesight. Another would be to serve as a shield for incoming attacks. It appears that Hoshigetsu can also keep this technique activated for a considerable amount of time, and even use it for offense, which would theoretically allow him to release multiple Getsuga Tenshō blasts at a single instant; however, these are not as strong alone as the original technique, but completely surpass the latter when fired together at a single opponent.


 * Kyōgetsu (杏月, Mirror Moon): Hoshigetsu can use the power of the Getsuga Tenshō as a reflective technique. According to Hoshigetsu, this is the ultimate indication of the mastery of Getsuga Tenshō. It allows Hoshigetsu to reverse the reishi charge of the normal Getsuga, and use it to attract the spiritual force of another. By doing this, Hoshigetsu can release an attack that easily surpasses the Getsuga, without causing long-term damage to himself.

Trivia

 * Like his wielder, his appearance is based on Allen Walkers from D.Gray-Man.