All For One

All For One, also known as The Eyes of Shared Power, is a powerful Longinus Class Sacred Gear that allows the user to gain the powers of others through theory and understanding.

Summary
Made by the God of the Bible to place emphasis upon humanity's limitless potential, God created All For One in order to give humans the ability to use the powers of other beings. Like humans, All For One was classified by God as a 'basic creation,' in which the first wielder would give All For One more powers and abilities for its successors to use.

Currently, there have been only two unknown wielders.

Appearance
All For One changes the user's eyes, signifying that the user is analyzing the most basic properties of the power being observed.

Abilities
All For One grants the user the ability to use the powers of other beings through theory and understanding, making All For One arguably the most versatile of the Sacred Gears. However, in adding powers to All For One's 'stockpile,' the user may also gain the weaknesses, but this has not been confirmed. Azazel says that, in theory, the user may also be able to make combinations of different base powers to create a more complex power, much like how elements combine to create compounds, though doing can be dangerous.

One For All
One For All is a power that allows the user to allow others access to a power that the user has in All For One's 'stockpile.' However, doing so requires physical contact with the subject receiving the power and it only lasts for two minutes. Placing new powers within the receiver, while it provides an edge and can potentially be a major game changer, the power may also cause negative consequences within the receiver and the user is also exempt from using that power given until after two minutes.

A previous user thoroughly integrated this power into All For One and it later became one of All For One's base powers.

Specific Powers Cancel
Specific Powers Cancel allows the user to cancel an opponent's access to a power, but only if the user has that same power within their 'stockpile.' For example, if the user of All For One analyzed and stockpiled Rias Gremory's Power of Destruction, then the user could cancel Rias Gremory's access to that power. When this power is activated, the user is able to disable an opponent's power only for as long as he concentrates on his target. The user only needs one part of the target's body to be within his sights for Specific Powers Cancel to take effect. Since most people in the world rely on their unique power sets for combat purposes, this makes the user an extremely bothersome opponent for anyone to deal with.

Avoiding the effects of this power is possible by covering one's entire body with clothing or some other material, or by hiding oneself from view through a solid, opaque structure. The power is also disabled is the user blinks or loses complete sight of the target. There is also a recharge interval between deactivation and a new activation, with the user requiring said interval to pass before he is allowed to use Specific Powers Cancel again.

A previous user thoroughly integrated this power into All For One and it later became one of All For One's base powers.

Trivia

 * All For One was heavily inspired by the Quirk of the same name, which is a special power used in the anime/manga My Hero Academia, or Boku no Hero Academia if you're annoying.
 * One of All For One's powers, One For All, was also based of a Quirk of the same name, but was heavily downgraded.
 * Specific Powers Cancel was based off Shouta Aizawa's Quirk, Erasure.
 * I might use this in a later fan fiction. If that happens, then I will update this.