Alternative names:

Game Gender: Female
Real life Gender: Male
Class: Shadow Warlock
Real Name: Iori Nakanishi
Age: 11
Avatar: The Machinator, Gorre
Supposedly a PC played by two people; Saku, who speaks in Kansai-ben, and Bo; a shy and quiet player. Saku is an alternate personality of Bo (albeit the much more forward of the pair), and is obsessed with Endrance.
Saku is very aggressive and holds grudges. Thinking of herself before others, she'll often do things like spend money painstakenly gathered by her brother without permission. Bo is very passive and affectionate, and looks up to Haseo as kind of a big brother. The opposite of his sister, he puts others before himself.
Contrary to Sakubo's claim of being siblings, both Saku and Bo are controlled by an eleven year-old boy named Iori Nakanishi (中西伊織). Saku appears to be a 'big sister' personality created by Iori in order to protect him against other people, hinting that Sakubo's player may have Multiple Personalities or Dissociative Identity Disorder. Iori originally had an older sister named Sakura (桜), but she was stillborn.

Related anime:

.hack//G.U. Returner OVA, 2007
.hack//G.U. Trilogy: Parody Mode Bonus, 2008

Related manga:

.hack//G.U.+ Manga, 2006
.hack//4 Koma Manga, 2007
.hack//G.U. Light Novel, 2007

Voice actors:

Megumi Toyoguchi, Japanese