The character of Graphite was conceived by Kuroto Dan, the teenage son of Genm CEO Masamune Dan. As a Bugster, Graphite's origin is traced to the Y2K bug, which left what would be known as the Bugster Virus on the younger Dan's computer shortly following New Year's 2000. Secretly incubating the virus by infecting the young Emu Hojo with it, Kuroto Dan would arrange for its matured form to be extracted by Michihiko Zaizen ten years later, using it to execute the Zero Day incident in the following year.

Graphite himself was spawned as a result of Zero Day, having been born from Saki Momose, girlfriend of Dr. Hiiro Kagami. During the incident, Graphite faced Taiga Hanaya as Kamen Rider Snipe Proto Shooting Gamer Level 1 and successfully defeated him. By thwarting the doctor Rider's operation to terminate him, Graphite ultimately achieved his perfected form as Saki sucuumbed to the Game Disease and perished. Graphite inherited Saki's memories, which he knew as "save data".

Five years after Zero Day, Graphite reported a new Bugster infection to Parado, proclaiming that they would soon be joined by an influx of comrades. Continuing the spread, Graphite asked Parado if he was sure that they should not be acting directly, to which Parado conceded that he may as well introduce himself as he set off.

Catching up with his old nemesis, Taiga Hanaya, Graphite was stopped short of settling what began five years ago by Parado, who dared Taiga to clear the most games and become the strongest Kamen Rider before the two departed. To create the next Bugster, Graphite infected coroner Yoshitaka Nishiwaki, kidnapping Niskiwaki's sister Riko to aggravate his stress.

In all these instances of the two squaring off, Graphite always held a tangible advantage in some form, whether it was just being a few levels above Taiga, being far better at close range or simply being unwilling to stay down and give the disgruntled Rider the satisfaction of revenge. However in other areas, he and fellow perfected Bugster Parad are quickly losing ground and Gashats to CR and their Riders, and looking to try and get a leg up on them, Graphite offers to hold the line and buy enough time for his friend to get help.

With that, Parad also suggests that with their shapeshifting abilities, Graphite could get into CR's good graces and take their lost Gashats back by disguising himself as Saki, the woman he killed and assimilated on Zero Day. As he keeps up this act and the gap in levels is successfully being closed by the Riders' efforts, he could feel more of her resurfacing and influencing his actions, starting with giving back the remaining Jet Combat and GiriGiri Chambara Gashats under the presumption of fair play, which is interrupted by a near-feral Lexx.

Eventually, he managed to successully buy time for Parad to get help from a prominent Power Player, a third Ex-Aid known as Kelly, except several things about her come off as odd to the reconsidering Bugster, but hadn't yet put his finger on it, up to asking why they're getting help from a Rider when CR's Riders specifically are their main enemies, but Parad brushes it off as unnecessary concern about the enemy of their enemy, only vaguely aware of what was really going on with the disguise.

It turns out that Graphite had started to feel more human the more it went on, finally grasping what it's like to feel, and how these experiences have made him more guilty as it went on, and what was supposed to be another ploy to earn the trust of CR and keep his cover ends up becoming an attempt to make amends in Hiiro's eyes as he and Kelly head off to take the Riders out of the picture.

However, the attempt by Saki at help almost becomes an exercise in Murphy's Law as everything that could've gone wrong went wrong, as Kelly proved too much for everyone everbody involved and kills most of the Riders present. It leaves her mentally in a shambles after only able to successfully save Hiiro and a feral Nico in the attack.

With the dust settling after this, it's clear to the the survivors and resurrected Riders that Saki is the Graphite Bugster, her having never considering that Poppy, who first points this out came to be under very similar circumstances. With all the guilt of her previous actions and her current situation rapidly building up in her again, she admits that it's the truth and she's willing to make amends for real. In coming clean about this, she reveals she still has a Bugvisor previously stolen and in her posession for the better part of a decade, and the ever-zealous Kuroto Dan relucantly lets her keep it, knowing she'll likely join the fellow Riders. This seems to be especially the case given Dan had previously demonstrated that the Bugvisor could become a different kind of Driver like the Gamer and Zapper Drivers, and it could likely work for her as well.

Since then, Saki has been consistently working to atone for her past as Graphite, to make it up to those that she had wronged over the years, starting with Asumi, who she failed to save from Aranbura and had become a Digimon as a consequence. She took on the responsibility of raising Lexx, Asumi and eventually Kuroto for this specific reason, reasoning that she can't do much else in the long run. She also tried dealing with Emu and Nico, who have been brainwashed into becoming servants of Evolt, where she also failed to help them simply because she couldn't turn them back. Taiga clearly accosts her for this, thinking that she's still Graphite despite all evidence to the contrary.

However, Blecker understands the issue more clearly and is clearly looking to find a solution to all this, not realizing a solution's already been put into place; the remnants of Emu and Nico meant to keep them off the real ones' trails. Correctly suspecting this to be the case, she enlists the help of Kamen Rider Odin to scour the city bring the real ones back to CR so their real selves. She however, seemingly wouldn't live to see this come to fruition as she would team up with her love Hiiro against the Bugster Hokutei in an effort to save Akira Jin. It would be a fight she gave her life for, but since she's a perfected Bugster, it may only be a matter of time until she returns again.