In the anime, it is revealed that Maira, a former Pawn, became a Bishop by gaining the ÄRM Vaqua. He is not given a backround in the manga. Maira is a black-cloaked masked man who takes pleasure in engulfing and digesting people with Vaqua. Vaqua is a blue/green slime-like Guardian ÄRM with one eye. Maira is first seen watching the War Game battle between Ginta Toramizu and Garon. During the second round of the War Games, Maira reappears as a fighter for the Chess Pieces. He has the last of the battles in that round, and goes up against Dorothy. Maira is quick to falsely judge Dorothy's power, though he easily destroys one of her weaker Guardians and stalemates another. Dorothy, however, calls back this one to bring about her favorite, Toto, which eats Maira's Vaqua. Maira, now ÄRM-less, begs Dorothy for mercy. Dorothy, however, doesn't do as such and has Toto eat Maira as well, becoming the first casualty of the War Games.
A member of Arc Aile who, like Cisqua, chose to use weapons rather than Edel Raid, Maina is an old friend of Cisqua. She appears in an episode of the anime to bring Ren back to HQ as the main Arc Aile trio uses the disguise of a vacation to help find Edel Garden. It turns out she was controlling a Sting Raid that was attacking people on the ship through song, but in the end Cisqua uses the song against her and has to kill her to prove her dedication to Ren. Cisqua also claims that Maina is the better sniper, but worse at everything else.
Maina is the mother of Moena and part of Angel Blade.
From Wikipedia: A genius blond-haired Akuma who recently got transferred to Tomoharu school and was put into his care from the Akuma hunt. Her family profession is to study the Asura Machina control systems. She's a Luck-eater, an Akuma that eats the luck of people and controls the balance between unlucky and lucky people. She was sent to study the Asura Machina that had absorbed the Stabilizer. She also came to Japan to look for her missing sister. After exident in 7th series she appeared in 1st Worlgв 5 years ago in the past and helped Naotaka and Ritsu in their Asura Machina research. She created Hagane and modified Kurogane for Tomo.
Suika is the only oni currently living above ground in Gensokyo, with the remainder of the oni race living underground. Just as the folktales say, she has two horns on her head that symbolize her oni heritage, and enough physical strength to throw large boulders single-handedly. Her personality is jolly and quite childish as you would expect from her appearance. She also likes to drink and loves to party with all her heart. Her power in the games is to manipulate density. (Source: Touhou Wikia)
Macha is the cat character that appears in .hack//SIGN and other .hack series. Although she appears to be a typical hacker or Vagrant AI, she is actually an alternate form of the Sixth Phase Macha the Temptress. She lures Tsukasa to a secret area, where Morganna can then manipulate him. After the events of SIGN she takes on the form Mia who resembles an older version of herself dressed as a warrior, and goes on adventures with Elk to find aromatic grass because Elk resembles the boy in her dreams(Tsukasa) who gave her aromatic grass in the first place. In .Hack//GU Endrance(an adult Elk) has the power to summon her true form into battle.
Mabaa (é”婆, Mabaa) is the current leader of all witches. She is held in high regards for being almost as powerful as Shinigami-sama. Her left eye was taken by Free which is now covered by a bandage with 1/2 written across it. Her specialty is Spatial Magic.