Grief

Grief is a human, who -due to insane experiments and torture- have achieved the Daibutsu State. He is involved in the prison break-out of Hamano Takumi.

Plot
Grief was first revealed when he, along with his team of fellow Daibutsu State humans, forcibly entered the Soul Society by unknown measures, to find and summon the Sokyoku. The leader of the group, Patch, then reveales that their true goal was to free Hamano Takumi, an S-classed criminal who used to be a Captain of the Gotei 13. Grief is given the task of distracting/maintaining the guards while Patch himself freed Hamano Takumi.

Daibutsu State
Grief is one of the five only humans capable of this "upgrade". It makes the subject more susceptible to Reiatsu, and then uses Reiatsu collected from Shinigami and Hollows to increase the inner power of the human, thus turning him or her into a Daibutsu State Human.

Reiatsu: As a Daibutsu State Human, Grief has an incredible amount of Reiatsu, but has the least of the group. Due to it being a mix of Hollow, Shinigami and human reiatsu, it is very extraordinary. Grief's Reiatsu is very fearfull, emanating constant -but silent- anger. Grief's Reiatsu is in a black and blue color, and behaves much like blades, sharp and concentrated but also full of horror and hate, used to violently break down the psyche of his foes.

Daibutsu Markings
Grief's Daibutsu Marking is centered on his forehead, taking a cross-like shape. It also has a bent line over it with a dot inside, made to symbolize "hunger", as the symbol is a bowl with wine. The cross underneath represents "Grief", as his own name implies. At the center of the cross, a whole circle is printed, made to represent "Will", as it symbolizes a sun. Two straight, short lines are then positioned horizontally on either side of the cross, made to represent "Judgement" and "Justice", as they symbolize a scale. When activated, the two horzontal lines, the "scales", open up like wounds, causing Grief to bleed from them. Also, all of the markings brighten up with ember-like intensity, glowing with his Reiatsu. Grief's hair color darkens when his Daibutsu Markings are activated. When his markings are activated, however, Grief has access to a number of mental powers, though they seem to pain him or tire him.
 * Mental Control: By focusing on a certain individual, Grief can take control of the person in question, manipulating him or her like a puppet. However, he cannot make the "puppet" talk on command, but can silence him or her if the victim tries to resist the power. It can be negated if something blocks the visionary link between them, to make Grief loose control of what is happening with his "puppet". Also, the technique requires some concentration, thus Grief cannot do anything while the technique is used. Strong enough Shinigami can resist it by overpowering Grief's own Reiatsu.
 * Mental Possesion: By giving up the ability to move his body, Grief can enter the mind of a chosen individual, taking complete control over him or her. Since he is constantly having a "battle" between who should retain the control of the body, Grief has to expell large amounts of Reiatsu to not get overwhelmed by the opponents own resistance. If this should happen, he would be forced out of the body and violently return to his own, caused much pain and fatigue. He can at all times return to his own body, but has to know exactly where it is, either by seeing it or simply remembering where he left it. It is unknown if Grief can access the special abilities of the Shinigami while using it, such as Kido or using their Zanpakuto's. If Grief has knocked out the opponent to make them unconscious before taking over their body, they will not resist it until they wake up, usually by taking damage in the body Grief inhabits.
 * Mental Blasts: A swift "blast" of Reiatsu is transferred from Grief to his opponents head, causing them to faint. Usually used to make it easier to possess someone, since the opponent would then be unconcious while Grief inhabits their body.