Weiss

Weiss (ワイス (白), Waisu German for "White") is an artificial being created by Oz, using the Black Box and several Hollow masks, granting Weiss attributes similar to an Inner Hollow and some powers from the Black Box. He is currently within Kaenjin Ouma and has been mistaken for a Hollow, which had evantually made Kaenjin an exile, Weiss' existence within Kaenjin is also what affected his mental state to some degree.

Appearance
Weiss claims to have no true form and that he can freely shapeshift to whoever he wishes, be it an animal, a monster or a Human, he tends to take the appearance of his current "host" merely to see how the form fits him, but gives the distinctive features an Inner Hollow would, which is completely white skin, white hair and black sclera but with white iris instead of the usual yellow.

However, Weiss' most frequent and favored form, is that of a pale skinned child with white sclera and black iris, spiky short silver hair with bangs and barely reaches to his shoulder. His attire is a simple white cloak with sleeves longer than his arms and a hood that conceals his head and shadows his face if not exposed to sunlight. He is short in height, but can change into a more adult form to reach the height he wishes. Weiss' expression is never changed, always being a stone face with no emotions.

Personality
Weiss' personality is just as his name means and the same as the Hollow mask he allows Kaenjin to don is, blank, as he is an emotionless figure, almost like a lifeless doll, showing absolutely no emotions, his intentions are also "blank", as he has none, he doesn't wish to gain power nor possess his host, he doesn't show any care for what happens around him nor to his host, the only reason Weiss gives Kaenjin power is merely, as he says, "has nothing better to do" and adds a sarcastic tone.

Kaenjin says that Weiss is just as blank as his Hollow mask, he doesn't think of anything, he doesn't need anything, he doesn't wish for anything, he doesn't even do anything when he is alone, the degree that Weiss shown these "blank" features is what makes Kaenjin call him the embodiment of "nothing" in physical form.

Powers & Abilities
Vast Spiritual Power: Having been created by the Black Box and have had shards of Hollow masks used to create him, Weiss contains both his own and a Hollow's spiritual energy mixed together, the part that was used from the Black Box further enhances his spiritual energy, granting Weiss a tremendous and uncontrollable amount of reiatsu that even te power of a Captain can't be compared to it. His spiritual energy is white in color, a reference to his already white skin and name meaning, with a black outline. Negative Energy Manipulation: A unique ability Weiss has that allows him to control and manipulate negative energy in any way he wishes and many different ways. The negative energy is white in color, but has a clear difference from Weiss' reiatsu, which is the black outline is present with his reiatsu and also the negative energy has more similarity to foggy smoke. This ability might hint that Weiss is negative and that he hides it. Shapeshifting: As a result of not having a true form, Weiss can become whoever and whatever he wishes hardly with any limits, he can turn into any thing in existence as long as it is a living creature. Weiss can alter the appearance he has taken, changing the hair, eye and even skin color to possibly anything he wants, he can even create an original face, which is the face of the form he is most frequently seen in.
 * Shockwave: By releasing a portion of his spiritual energy, Weiss can create devastating shockwaves around him, damaging those surroundin him, leaving him unharmed by the power of his shockwaves.
 * Negative Energy Constructs: Weiss can construct and soldify the negative energy he controls in order to form weapons, tools, objects or other kind of solid material, being useful in battle, though Weiss has used this in order to construct things such as houses, furniture and statues, showing the constructs are long lasting.

High-Speed Regeneration: Thanks to his Hollow side, Weiss can instantly regenerate wounds and regrow missing limbs.

Weiss' cero is remarkably powerful even though it is a normal cero fired.

Crystalization: As a result of having the Black Box used to create him, Weiss is able of crystalizing anything that he chooses when coming in contact with it, the crystalization works by soldifying the matter that constructs the body of his target, such as reishi which makes up a Soul and Shinigami alike, the end process of that short soldification is of course crystalization like results. He can also use his own spiritual energy to do the process and make it faster and easier. The crystals have one primary color, it being dark purple.

Enviroment Control: While inside Kaenjin's inner world, Weiss can freely control it and change the enviroment around him through sheer will, this can work to his advantage in battle, if any even occurs. Weiss changes the inner world very often to pass the time, leaving Kaenjin's inner world's original form unknown.

Trivia

 * Weiss' appearance is based off Fate Averruncus from Mahou Sensei Negima?!.
 * Weiss can be considered the "White" in Bleach: Black & White, this is further supported by the fact his name means "White" in German and also for his "blank" personality.