Onsa (調律 lit. "Tuning Fork") Onsa can control and manipulate sound waves.
When seales Onsa takes the shape of a normal katana with a single exception. The blade of the sword has seven holes drilled into the side, each increasing in size as it gets closer to the hilt. Both the hilt and sheath are a deep magenta. The guard is black and takes the shape of a triangle with the two larger angles in back. The front of the triangle, also the smallest corner, blends into a small bar that runs down in front of the weilder's fingers. The bar is also shapes like a musical note with a small ball at the end facing forward.
Onsa is a very particular zanpakuto in the fact that is has a special ability while in its sealed state. When swung, Onsa lets out a high pitched whistling sound after a moment's delay. The enemy can be thrown off between the difference of when they hear the attack when they see it, causing their reaction time to be off.
Onsa is released with the command "Keiteki, Onsa." (lit. "Whistle, Onsa").
When released, Onsa's blade splits into a 'V' shape with elongated ends, thus taking on the form of a tuning fork. Unlike a tuning fork, both prongs are still sharp like a sword. The holes in the blade also disappear. The hilt loses its original curved shape and becomes straight so that either blade can be used to fight.
Onsa's released form still has the same delayed sound effect as before, but gains two additional abilities. The first ability is called Yuri (揺 lit. "Vibration"). Yuri causes Onsa's two blades toconstantly vibrate faster than the eye can see. This high speed vibration drastically increases Onsa's cutting ability to that of a small chainsaw. This also makes blocking the sword very difficult. When an object comes in contact with Onsa's released state, its pulses slightly repell it, making it hard to block. Even if an enemy manages to blck the blade, its small, but powerful tremors travel through their sword and damage their arm.
Onpa (波 lit. "Sound Wave") Onsa's second ability comes from its power to manipulate sound waves. When struck, the weilder can harness the vibration in between the two prongs and release it with a simple swing, causing an amplified blast of sonic energy. The downfall of this attack is taht the sound waves cann actually be seen, so dodging is possible. The blast takes the form of hollow intertwinning circles that stretch out until the attack is either ended, or has hit something. Unfortunately, the attack is only a straight shot and cannot change velocity.
Shizuka na Himei Onsa (lit. "Silent Screaming Tuning Fork"). Onsa's size and shape also changes from a regular sword to an enormous tuning fork with thicker sguared prongs instead of its previous bladed ones. The loss of the blades doesn't comprimise Onsa's ability to cut an opponent, however. The additional weight of the weapon does not effect the speed or strength of the weilder. The user also gains a black and silver visor that hide their eyes.
Onsa's bankai ability attacks the enemy's senses. Everything within the area becomes completely inaudible, meaning that no one, other than the weilder, can hear anything. Even zanpakuto become oblivious to their owner, making it almost impossible release it or cast Kido spells. The enemy's vision is also impared. Everything the enemy see become black and white. Any motion also has a small delay before the enemy can see it, similar to Onsa's sealed ability. The visor worn by Onsa's weilder cancels out its effects, so they can still see and hear properly. The visor also has another ability, that allows the weilder to see sound waves that resemble ripples. While in its bankai, Onsa can still use all its shikai powers. One major weakness Onsa has yet to overcome is through the visor. If an enemy ever had the chance to steal the visual aid, the user would become suseptable to Onsa's bankai ability. Anyone who wears the visor is granted with the enhances senses.
Onsa takes the form of an old man with long white hair and a red vest. His body is frail and his movements are slow. The man also appears to be blind, def and dumb, as he has never responded to any sound, has white pupils and has never spoken. Regardless, the old man is extremely wise and observant. His teachings are based on patience and understanding. He can communicate with his owner telepathically through emotions.