Upon the Tainted Sorrow

Upon the Tainted Sorrow (汚れっちまった悲しみに,) is the ability of Chūya Nakahara.

Description
Upon the Tainted Sorrow allows Chūya to manipulate the gravity of any object or individual he gets in contact with. As such, he can change the direction and force of gravity from its standard downward 1G force, as long as the matter is touched somewhere with his body.

Chūya typically uses his ability for offensive purposes. He can manipulate physical matter from the surrounding area, such as the ground he is in, to use as his weapon and launch at his opponents, crushing them with the force-enhanced matter. Regardless of its size, the object can inflict massive destructive force when its gravity is altered to a greater strength and force. He can also stop bullets shot at him and deflect them back to their sources.

Moreover, Chūya can directly control people's physical gravities. When manipulating his opponents' gravities, he can immobilize their movements by making their bodies heavy or light enough to render them incapacitated. For instance, he can make them levitate by lightening their masses and immediately plunge them to the ground with a heavy force.

He can also manipulate his own gravity as he deems fit. He can decrease his body's gravity to lighten his mass while attacking at high speed; as a result, his kicks released at high speed can pierce through his targets with the weight of an iron ball. In addition, he can control his gravity and allow himself to sprint at overwhelming speeds and reflexes without losing momentum. Chūya can also manipulate his gravity that can allow him to stand upside down on the ceiling, ride his motorcycle sideways on the face of a building, and even walk on an airborne plane's flap with relative ease.

Notably, his ability is quite incompatible with Ryūrō Hirotsu's repulsion ability, as Chūya can control the force of matter upon contact, while Hirotsu can apply an opposite force relative to the contact surface. Moreover, since Upon the Tainted Sorrow is fundamentally anchored on the laws of gravity to function, it has a natural weakness to Arthur Rimbaud's subspaces which do not adhere to the laws of physics. As such, Chūya cannot defend himself against Rimbaud's massless spatial waves, nor can he easily utilize his ability as he usually does in the natural, physical setting. Furthermore, like all other abilities, Osamu Dazai can nullify Chūya's ability upon contact.

Corruption
Corruption (汚濁,) is the true form of Chūya's ability and is exceedingly dangerous. This ability allows him to manipulate the gravitons in his surroundings. By increasing his own density, he is capable of crushing a tank with his bare hands. He is also able to shoot balls of compressed gravity that act like black holes that swallow anything. However, he has no control over his Ability's true form; he will continue in that state if his Ability is not nullified until he dies.

It stems from Chūya's origins as the entity Arahabaki, a God of immense destructive power. When Chūya releases his stability over said powers, Corruption takes over, essentially reverting Chūya to his true, uncontrollable nature existing solely for destruction. Paying homage to his own philosophies, Chūya removes his gloves when activating Corruption. It is activated by the verses:

Though granted with immense power and strength, Chūya has no control over his ability's true form. As such, he will continue in that state until he dies unless his ability is nullified. Hence, No Longer Human is thus far the only way to stop Chūya's Corruption-fueled rampages.

Moves

 * Gravity Control (重力操作,): Considered as the core of his ability, Chūya's gravity manipulation allows him to control any matter's gravity. As such, by touching his target, he can increase the mass of his opponent by punch through his body and render him immobile indefinitely. Chūya can also propel bare bullets and launch it at his targets akin to being fired by usual armament.

Derivation
The ability is a reference to the real-life Chūya Nakahara's poem entitled This Soiled Sorrow (汚れっちまった悲しみに,), which was published in 1934. Chūya's precursor verses to activate Corruption are lines taken from his author counterpart's poem, Lament of the Lamb (羊の歌,), which was written by Nakahara to Yoshihiro Yasuhara.