Just for the record, Pai's name is actually Pi. They didn't get it wrong in the US translation; it was actually meant to refer to the number Pi.
Taken from the .hack wiki:
# Pi's name comes from the number π, which she believes represents herself: an indivisible and unbreakable woman. # Pi's name was originally written as "Pai" in Japanese sources. However, this turned out to be a mistake.
shit, man... do you actually get all these chicks as allies in the G.U. games??? (PS... Pi is actually Ender from the anime for those who've never watched it)