The HOLON III or simply HOLON is a supercomputer owned and used by The Eleventh, John Bacchus. It serves as a key device before and on the series timeline.
The HOLON is a supercomputer composed of three servers at different locations. According to John, the HOLON is Japan's third most powerful supercomputer. True to this the HOLON has shown extraordinary processing and data hosting abilities, which John used to give everybody in Sakurami City an account to log in a special blog.
The HOLON was used in conjunction with The Eighth, Kamado Ueshita's Blog Diary to give every inhabitant of Sakurami City an Apprentice Diary. The fact that mostly each citizen could have an Apprentice Diary with only a day of connection to the HOLON, is itself an impressive feat, as it is known (although never directly stated) that Kamado's Diary cannot give an Apprentice Diary on a whim but rather needs successive posts from a user on its blog to give one. This meaning that the HOLON is in fact capable of giving The Blog Diary an incredibly boost in power that seemingly bypasses this rule.
Because the HOLON runs with three servers, destroying only one of them, has little to no real effect on the supercomputer's overall powerful. It is known that also that the last two must be destroyed at the same time to have a real effect (although a true coordinated attack on the two last servers is never seen though).
One server is located in Sakurami Central University, and the other two in the top floors of the Quad Towers.
Not known is much about how or when the HOLON III came into existence. In the anime's 24th episode Data Retrieval it is shown that the HOLON has existed since at least 2 years prior to the series timeline and was used by John to create the very first prototypes of the Future Diaries. It is shown that the HOLON's processing power as already very powerful at the time and allowed the creation of the Diaries to be faster than expected, as well as the prototypes themselves being capable of giving the HOLON even more power.
The Eleventh's Kingdom
The HOLON is unheard of and not seen until very late on the series when it makes its first appearance. John who had escaped with Ueshita an attack from The First, Yukiteru Amano and The Second, Yuno Gasai go to Sakurami Central University, where Balks reveals a server of the HOLON to Ueshita. Balks then announces his plan to use the HOLON to enhance The Blog Diary to give Sakurami City the power of the Future Diaries which he sees as his ideal of a superior race. Following this, The Ninth, Minene Uryu who had infiltrated attempts to blow the computer but to no avail as Balks easily catches her grenade and throws it back to her. With Minene trying to escape, Balks uses this chance to have his secretary connect The Blog Diary to the HOLON, which he does quickly. Minene and Masumi Nishijima team up to blow the computer, albeit to no avail as they only destroyed one server and The Blog Diary was already uploaded into the HOLON, throwing the Sakurami City into chaos from the mass of Apprentices that use them for evil deeds.
Minene, Nishijima with Hinata Hino, Mao Nonosaka and Ouji Kosaka team to try to destroy the two remaining servers in The Twin Towers of Downtown, but were unsuccessful as John has his personal army to corner them. However using confusion, both Yuki and Yuno successfully infiltrate the towers and are capable of easily decimating what's left of John's guard which leaves the servers unprotected. Their destruction is only seen in the anime, where Yuki shots the servers down. With its destruction it is implied that The Blog Diary returned to its more limited form and any new Apprentices during this time may have been lost.
The Third World
The HOLON is likewise seen only in the anime at this point. With the changes in the future within the third world, John abandons the Future Diary project, therefore it is unknown if he is still in possession of the HOLON or no longer uses it having no major need for it.
- The number III on its name represents many things akin to its number. Such as having three servers, being the 3rd most powerful of the country, or even its owner John that is the 3rd to last participant to die.
- The HOLON possibly takes its name from The Holon Institute of Technology and also from the Greek word "holon" that is something that is a whole and a part, which aptly follows its composition.