Fusai was a planet where the Rebel Alliance maintained a records office during their conflict with the Galactic Empire. Around the time of a siege at the Alliance's Outer Rim based Sunspot Prison in 0 ABY, the rebel protocol droid C-3PO learned from a rebel R5 astromech droid unit that the Fusai office needed protocol droid personnel.
Following the prison siege, C-3PO informed the astromech R2-D2 of his intention to request a transfer to the records office, believing the work to be both more suitable and safer. R2-D2 then inquired about accompanying C-3PO, but the protocol droid responded that this was impossible as there were no positions for astromechs available at the office.
The planet Fusai is mentioned within current Star Wars canon in the nineteenth edition of the 2015 comic book series titled Star Wars. This edition was authored by Jason Aaron and released by Marvel Comics on May 25th, 2016.
Within the Star Wars Legends continuity, the world Fusai initially appeared, though without being named, as the location of the BRT supercomputer Mistress Mnemos in the comic story "Gambler's World." This story was both written and drawn by Russ Manning and was published between March 12th and September 8th, 1979 as a part of the daily Star Wars comic strip that was distributed by the Los Angeles Times Syndicate to major newspapers in America and Canada from 1979 until 1984. The reference book The New Essential Guide to Droids, from 2006 and written by Daniel Wallace, later identified the location of Mnemos' installation as Fusai.