|Place of Origin|| United States|
|Portrayed by|| Unknown |
|List of Tachyon's blogs|
Tachyon is the codename of an operative who infiltrated Operation APHID as a double agent. The main enemy of OpAphid, Tachyon grew up in a Hymn of One commune similar to Bree and Gemma, but learned the truth about the Order at a young age. Tachyon's family moved away from the commune after learning that Tachyon's sister was being prepared for the Ceremony, and left their dog Sascha behind. Living on the run with a Resistance movement known as the Family, Tachyon interacts in her videos with her partner Brother and the head of the organization, codenamed Mom and Dad.
Tachyon is first introduced when OpAphid informs the viewers that someone had stolen a significant amount of confidential information from one of their information-gathering facilities, and asked us to track the thief for clues about what information had been stolen and where it might be headed. Further search revealed the thief to be Tachyon, a spy for another secret organization known sometimes as The Family, The Bureau, The Ring, or just Mom and Dad. Also, "tachyon" was used as a tag in some of Bree's videos. A user looked up all the strange tags and found that Tachyon's videos were similar to OpAphid with a similar story to Bree. When users subscribed to Tachyon, her videos were pulled until the release of The Action of an Enemy - Be Careful.
For reasons unknown to us, Tachyon has not chosen, or has not been able, to go "home" to Mom and Dad. Instead, she has conveyed her stolen information, as well as anything new that she learns or discovers, through her partner, codenamed "Brother" or "10033." Brother and Tachyon, who are not actually related, communicate through voicemail, YouTube profile updates, and drops, or physical locations where Tachyon leaves items for Brother to recover. It appears that although Tachyon frequently finds Brother irritating, dense, and slow, she does what she can to protect and help him (such as keeping OpAphid from blowing him up, and facilitating his attack on Gemma).
Tachyon herself is well-characterized by her YouTube tagline about her location: "By the time you know, I'll already be gone." She responds to some people who send her messages via YouTube, but her replies can be witty, helpful, vague, misleading, or simply unrelated to the question asked, seemingly on a whim. She dislikes giving out information about herself or her past, although some of her communication has suggested that she might be connected to the family Gemma talks about in her video "They Disappeared...," even as the information she leaves behind reveals more and more about her own personal story. Tachyon does not appear to stay in one place for any length of time, if she can help it, and is extremely fond of codes and cryptography, which she often employs to protect the information she distributes.
Tachyon was contacted by Bree after Daniel was abducted by OpAphid and The Cowboy. Bree posted a video pretending that she would give herself up to the Order in exchange for Daniel's safety as part of a ruse orchestrated by Tachyon and Brother. On the day of the exchange, Daniel was successfully rescued, and Tachyon and Brother went on their way. A little over a week later, Tachyon delivered a package to Daniel containing an encrypted file containing information on the Order and their inner workings. After the resulting knowledge caused a fight between Bree and Jonas, Bree decided to spend time at Tachyon's Training Camp, where she learned basic skills on how to defend herself. She left the training regiment early, however, as she discovers that Daniel and Jonas are in danger.
- Main article: Aly Zarin
In July 2007, Linc contacted Brother, believing Tachyon to be dead. Upon receiving the information, Brother got Tachyon to come out of hiding, and sent her a message from Linc containing information on how to help him and Rachel. Less than two months after the message was decoded, Rachel resurfaced on YouTube and assured everyone that she was fine, but revealed that she had fled from Linc. Tachyon has since been assigned to monitor Rachel in Linc's absence using the alias Aly Zarin.
There has been much speculation as to the true identity of Tachyon, especially after the video The Human Ransom. A video posted by xitsMx suggests that Tachyon is indeed Cassie, and some fans also think this could be the case. Others have suggested that she is the girl that Gemma mentioned in the video They Disappeared.... Some have even gone so far as to suggest that it is Gemma herself. There has also been more tentative speculation that Tachyon may be Nikki Bower, and although there are some links and similarities, it is a much more abstract thought to prove.
A member of the LG15 community once sent Tachyon a message asking how Sascha was doing. Sascha is the pet dog of the family Gemma mentioned in the video They Disappeared.... Tachyon responded that she hadn't seen Sascha in a while. This confirmed that she was in fact a member of the family Gemma spoke of. However, Tachyon has also said she was never a Ceremony girl, leading people to believe that Tachyon is the sister of the trait positive girl in that family.
- While Glenn Rubenstein was still working for lonelygirl15, there were talks that Tachyon would replace Bree as the main female protagonist if Jessica Lee Rose left the show. It therefore bummed him out when Miles Beckett suggested that Tachyon would be better off as an unseen character, for he was afraid that she would just get reduced to a "camera angle." However, in the long term Glenn admits that Miles was probably right, as Tachyon's unseen status helped him as he was coming up with the idea for Redearth88.  
|Main Characters||Bree · Daniel · Jonas · Sarah · Taylor · Emma · Jennie · Gina|
|Supporting Characters||Gemma · OpAphid · Tachyon · Alex · Carl · Spencer · Mallory · Dr. Hart|
|Recurring Characters||Lucy · Nikki B · Virgil · Elizabeth Avery · Bree's Watcher · Brother · Sonia · Jules · The Whartons · Claire · Edward Salinas|
|Full Character List|
|LG15: Outbreak Characters|
|Main Characters||Mason · Crystal · Will · Emma|
|Current Supporting Characters||Spencer · Jordan · Jessica · Mitchell · Francis LaFleur · eyeseeyou · Alizee|
|Full Character List|
|OpAphid ARG Characters|
|Main Characters||OpAphid · Tachyon · Brother · War Pylol|
|Recurring Characters||Cassie · Bree · Daniel · Gemma · Mom and Dad · Lucy|
|Full Character List|
|Main Characters||Rachel · Tachyon · Brother · OpAphid · Linc · War Pylol|
|Supporting & Guest Characters||Bucket · 15over15 · Doctor · Gregory|
|Additional Characters||Dr. Arscott · Jordan · Rachel's parents · Rachel's grandfather · Rachel's boss · Rachel's boss's wife · Rachel's co-workers · Zoey · Maddison · Rachel's landlord · Larry · Brother's wife · Milo · Eric|