Fairy Pieces

Fairy Pieces, Also known as Piece of Recolocation, is a special, prototype type of Evil Piece created by Mary Beelzebub in the Highschool DxD: Яe-birth continuity. Said from her in order to create even more interesting Rating Games for her husband, as well as deepened the bond a High-class devil has with its servants.

Summary
During some time before the canon events, Mary Beelzebub developed her own version of the Evil Pieces created by her predecessor Ajuka Beelzebub in order to both develop his own creation out of spite and make the Rating Games more interesting. For being prototypes, the Fairy Pieces have been distribuited only to the families of her fellow Satans, the heirs of the Astaroth and her daughter since they were the young devils of most developed power, with eight pieces each.

Berolina would receive her share after the events of Volume 11, in which she was deem worth of such.

Appearance
For being still prototypes, the Fairy Pieces are pieces of the Evil Piece material caged inside a magical glass protection, which needs to be broken in order for the user to take use of it, in which they'll morph to the desired piece.

When the King uses Anti-promotion, the rock instead becomes an unstable black mass which covers an eerie aura around the user.

Abilities
Based on the concept of Evil Pieces and the Pawn's promotion move, the Fairy Pieces allows the pieces who use them to use other attributes from other pieces. By channeling their power so it can indetify the Evil Pieces of the servants, the Evil Piece will grant an extra boost in other stats for a limited time, as of the followings: Naturally, for that order, Queen and pawn pieces can't use Fairy Pieces.
 * A bishop or a Knight who chooses the other piece will become a Princess Piece, with both magical afinity and speed.
 * A Knight or a Rook who chooses the other piece will become an Empress Piece, and have both speed and strength.
 * A Bishop or a Rook who chooses the other piece will become a Proto-Queen Piece, and gain both a boost of speed and strength/endurance.

Anti-Promotion
Anti-promotion, also known as Royal Coronation, is the occasion when the King of the Peerage uses the Fairy Piece. Instead of gaining any boost in their abilities, instead they have the power to channel any abitilies from any of their pieces and temporarily use them as their own. This move is only allowed once the piece called is out of comission or absent of the fight, but still present in the Rating Game overally. By using the Fairy Pieces, Kings can channel their Evil Pieces' signature moves at the cost of one piece of each use and the shared stamina between them and their pieces.

Berolina Gremory's peerage
The Peerage of Berolina Gremory composed of six pieces as for now:
 * Queen(Ichijou): By channeling her Queen, Berolina is able to create powerful blasts of dragonic energy and have the ability to summon an copy of Ichijou's signature weapon, Ix.
 * Knight(Annabelle): By channeling her first Knight, Berolina can reach faster-than-sound speed in a mere of seconds, as well as the ability to summon another familiar by the name of Alfred, Annabelle's ninja turtle.
 * Knight(Guan Yu): Now channeling her second Knight, Berolina has a boost of energy and the ability to completely mask her presence from her enemies.
 * Bishop(Tasha): By channeling her first Bishop, Berolina gains the ability to conjure hotter than ice flames from the Campbell family, as well as more knowledge in general magic due to her link with Tasha.7
 * Bishop(Whiswain): By channeling her second Bishop, Berolina can create from her Power of Destruction a mantle that makes her invisible, and allows her to pass through walls and create a corrosive miasma.
 * Rook(Liu Bei): By channeling her Rook Piece allows Berolina to access Liu Bei's tai chi abilities, which means she can temporarily turn immune to holy weapons, as well as her super-strength.

Alice Berith's Peerage:
The peerage of Alice Berith, composed of four pieces as for now:
 * Queen(Nene Sumeragi): By channeling her Queen allows Alice to create several exorcism seals within her body, which aren't harmful for herself, which can seal almost anything.
 * Knight(Shinra Saotome): By channeling her Knight piece allows Alice to have a boost in her speed and precision, as well the ability to create a sword made out of the Berith's black flames which serves as a replica of Shinra's Claiomh Solais.
 * Bishop(Zero): By channeling her Knight piece allows Alice to have access to Zero's impressive healing magic skills, which can mend flesh and repair bones in an outstanding manner similar to the Phenex's healing faction.
 * Rook(Andromeda): By channeling her Rook Piece allows Alice to recreate's Andromeda's godly strength and her chains made out of black flames.

Granzboa Astaroth's Peerage
Unknown.

Irene Dantalion's Peerage
The peerage lead by Irene Dantalion which is composed by 8 pieces: TBA

Trivia

 * The concept is named after Fairy Pieces, a name given to variations of chess with different names. The image used for it is from the Hogyouku from Bleach.
 * According to Mary, Fairy pieces cannot be used to reincarnate someone as a Devil. However, they can estimate which Evil Piece is best for someone to be reincarnated as.