- "Be careful, there's a dangerous power hidden inside of you."
- — Pi —
Pi is a scantily clad Tribal Grappler. She has long pink hair tied into two large pigtails and wears a very revealing red outfit which snakes down her legs. She wears a small pair of glasses on her face which she frequently fiddles around with when trying to make a point.
As Yata's assistant, Pi is required to follow his orders, a job she does willingly. However, unlike Yata, she has trouble seeing The World R:2 and its users in an impersonal way. She has the tendency to become attached to people and occasionally breaks the rules in order to help them out. Despite the tough personality she tries to give off, she is prone to occasional moments of weakness, especially when dealing with other people. Nevertheless she is dedicated to both her job and to Yata and does her best to follow his commands. She is fairly close to the other members of Raven especially Kuhn, though she insists that she only sees him as a coworker. Pi had a very strained relationship with Haseo. Though she recognizes his skill and power, she initially saw him as nothing more than a rude brat with no manners whatsoever, and considered his personality dangerous based on experiences from her own past. She and Haseo gradually built up a deeper relationship and understanding of each other, however.
- Pi's offline self is a woman currently residing in Tokyo named Reiko Saeki (佐伯令子). She is a workaholic, loves eating out, has a pet cat and is younger half sister of programmer Jun Bansyoya. In 2016, she suddenly quit her job as a programmer to work at CC Corp. Saeki enjoys driving and owns a Maserati.
The final file on the Terminal Disc is a letter to Reiko from Jun Bansyoya. He reveals that he's her brother, though they haven't seen each other since she was very little. He tells her that she's a Chosen One, and that the Epitaph PC for Tarvos is on his PC
For more information, see Ender.
Reiko played as Ender until TaN was disbanded and then resumed her true form as Pi. She was then assigned by Yata to track the remaining members of the Twilight Brigade, namely Tabby and Haseo. To help her with her work she restored the account of Saburou, a player who had worked for her in TaN. Saburou directly interacted with the two players while Pi watched from the sidelines. However Saburou soon realized that Pi had more power than a normal player should. When she confronted Pi about it, she became angry with the evasive answers Pi gave her and resigned as her assistant.
Soon afterward Tawaraya returned to The World using the character Tohta. Feeling guilty about the loss of his character, Pi contacted him, but Tohta easily saw through her disguise and recognized her as Ender. He used her to contact Yata and pulled in a favor by requesting that he delete several Real Money Trade players.
Pi was then called in to contact Kuhn, who had awoken his Avatar after coming into contact with an AIDA. She invited Kuhn to join Raven and promised to instruct him on the use of his Avatar. Realizing that there was a serious threat to R:2, Kuhn accepted her offer and left Canard to join up with her and Yata. The two began hunting AIDA together. However their hunt was put on hold when Tri-Edge reappeared and attacked Haseo. Realizing that Haseo's own avatar was about to awaken Yata began making plans to bring him into Raven as well.
At Yata's orders Pi finds herself busy keeping track of the Epitaph User Endrance and his progress in the Arena. Unfortunately for her, her partner Kuhn seems more interested in Nanase than the jobs Yata sets for him.
When Haseo is about to be PKed by Bordeaux, Pi saves him, then leaves, after commenting about a "dangerous power" in his character. She begins to resent Haseo because of how disrespectful he is to her, like calling her an "old hag." She accompanies Kuhn to train Haseo at Δ Great Cursed In-Laws. There, they share with him their knowledge of the Avatars. Although Haseo tries to summon an Avatar for a while, he is unable to do so. Pi begins to provoke him, saying he isn't worthy enough to use an Avatar, but leaves when Kuhn tells her to stop. After they return to Mac Anu and Kuhn leaves, Pi tells Haseo that she came along so both she and Kuhn would be able to stop Haseo if he lost control of his Avatar. Pi states that she and Haseo are very much alike because of their desire to control their Avatar's power.
Pi plays a major role later on as a member of G.U. and is able to summon Avatar Tarvos. During a training mission with Haseo, she ended up getting infected with an AIDA, which in turn forced Haseo into his first battle against another Avatar. Later Pi was one of the two party members to aid Haseo in fighting Azure Kite.
In the comic Pi is a manager in the net game The World. After Haseo is defeated by Tri-Edge she introduces herself as a member of G.U. and explains about a phenomena in the game known as AIDA. At Dead World of Indieglut Lugh Bordeaux is possessed by AIDA and Pi arrives with another member of G.U named Kuhn to intervene. After Haseo is saved, Kuhn explains that the AIDA are beings that can infect people and fuse with their minds. Kuhn also explains that the Epitaph Users are the only power capable of combating them. Following their conversation Pi introduces Kuhn as the Epitaph User known as The Propagation and the doll that saved Haseo is Kuhn's Avatar Magus. As Kuhn adds that Haseo is also an Epitaph User Haseo demands to learn how to use the Avatars. Pi begin tells Haseo to listen and do exactly as she says however Kuhn interrupts her and asks Haseo to come with him if that is what he really wants. Afterward Pi returns to the Serpent of Lore. As Haseo enters battle in the Arena Yata explains to Pi that the AIDA are interested in strong human emotions and Pi watches from the monitor as Haseo activates his Avatar Skeith for the first time in his faces off against Endrance.
In the novel Reiko Saeki investigates AIDA through her character Pi as a system engineer of Project G.U. for the CC Corporation. As a result Reiko becomes immersed in the Bansyoya File written by her brother Jun Bansyoya and the fonder of Project G.U. Throughout her journey Reiko investigates the project and visits the translator W.B. Yates, behind the former PC Hotoko, real name Mizuhara Haruka, to learn about The Epitaph of Twilight written in her brother's report. Much after with the information behind her Reiko Saeki as Pi later rescues Ryou Masaki's character Haseo and introduces him to Raven. When Atoli disappears Pi tracks her whereabouts to Morrigu Barrow. Along with Kuhn and Haseo, Pi travels to Outer Space to find Atoli where they unexpectedly face Tri Edge. Unfortunately before they can ask how to recover the Lost Ones Haseo uses his Avatar Skeith to use Data Drain against Tri Edge and Pi delivers the final blow with her Avatar The Avenger Tarvos, knuckles with spike like beasts' claws.
Soon after the incident however Atoli's Avatar is stolen and Pi is taken into the AIDA Server with the rest of The World. Reiko later escapes with everyone else using the AIDA Server Operations Folder and as time passes even schedules an appointment in Ikebukoro to meet with Ryo to discuss the condition of Atoli's player Chigusa Kasaka. Following this at Raven's @Home Pi restrains Endrance as the members of G.U. attempt to review what the avatars are when Yata presents the sixth Bansyoya File.
- The Gauntlets Pi starts out with are the Tiger Fist, a rare set of Gauntlets.
- Pi's name comes from the number π, which she believes represents herself: an indivisible and unbreakable woman.
- Pi's Japanese voice actress, Sanae Kobayashi, also does the voice of Mai Minase from .hack//Liminality.
- Pi's name was originally written as "Pai" in Japanese sources.
- Pi is 5'8" (175 cm) in height. According to Reiko, her measurements are 37-22-33".
- In the .hack//G.U. Prototype Trailer, early concept sketches had her being a Twin Blade, as well as wearing a less revealing attire.
- One of Pi's earlier concept sketches was later used in the G.U. games as one of the minor PCs Haseo can interact with.
|The Infinity Eight.|
|Haseo's party members.|
|Alkaid||Antares||Atoli||Asta (Temp)||Azure Balmung|
|Azure Kite||Azure Orca||Bordeaux||Endrance||Gaspard|
|Pi||Piros the 3rd||Sakubo||Shino||Silabus|