Caído

The Caído (Spanish for Fallen) are a group of former Shinigami ,Vizards and Arrancar who have been converted into near humans by the use of the Kaihō(解放, Liberation). The first of their kind was Sasuke Sarutobi who created the Kaihō by mistake while trying to find a way to reverse the hollowfication of his best friend and later himself. They all retain their shinigami and hollow powers but are neither, being almost human with almost full control over their inner hollow. They are best described as being more of a hybrid of all the three races than being any one alone.

Their souls are different from the souls of shinigami, hollows or humans. During their creation by the Kaihō, their soul and inner hollow are split into separate entities and the separate souls leave their body. The person appears to die and then the Kaihō takes their Reiatsu to merge both the souls into one entity. The new soul is then returned into physical form and an apparent rebirth takes place. Due to this they gain a body that possesses nearly all the properties of a human body.

One of their few differences from human shinigami is that unlike them they can use their spiritual powers to some extent in human form itself, but to release their shikai and bankai, or use their hollow powers they need to to separate their soul from their physical body and go into spirit. After training they can leave their bodies on their own without requiring any skull symbols.

They are at complete peace with their inner hollow and as such can call upon and use their full hollow powers at any time without any risk of their inner hollow taking over as it is now a much more integral part of them. Though the inner hollow form is stripped of almost all of its power, it can still manifest itself at times of grave danger.

List of Caído Abilities
Increase in Spiritual Pressure: The Caído undergo a increase in their Reiatsu levels by a factor that varies from around 5 to 15 depending on the beings strength before the transformation.

Regeneration: All Caído gain the ability of high speed regeneration. They can regrow all but their vital organs.

Increase in Speed and Strength: They gain an increase in their overall speed, speed of reactions and also their strength in human and spirit form.

Lifespan: Though they now appear human, they still retain the long lifespan of Shinigami.

Hollow Form: They gain the ability to use their inner hollow's full powers while retaining complete control.

Dos Artes (ドスアルテス, Gear Two): Similar to a Arrancar's Resurrección, they also gain a new form which they can use call Dos Artes or Two Arts. In this form their powers are drastically increased and they can bring their full powers to bear. They transform into a shinigami hollow hybrid completely and their body changes so as to appear more like a Vasto Lorde and their powers can easily compare to one. In this form they take on the appearance of their inner hollow but with one difference, their irises appear blue instead of yellow.

Fatal Flaw
Despite their great strengths, the Caído have one fatal flaw. As their souls are created by the merging of two parts, there is a natural repulsion between the two parts. While their transformation, all of this repulsion is removed and condensed into one point. This point is different for every Caído but it stays fixed at one location on the body for every one of them. If that point is attacked with a large enough amount of spiritual energy, the union will fall apart and the person will subsequently be stripped of all their powers leading to their death.