Alias: Silas Greypaw - used to blend in as a "normal" kat.

Born in a computer, Sypher's start on life was as an artificially intelligent computer program created by Dark Kat. Part of Dark Kat's plan to create more intelligent help, his programming was infused with DNA sequencing and then routed through a conversion that transferred him from so much data and a strand of energy to a solid form. Thus born, he became Dark Kat's head assistant.

Though usually appearing as a kat he never lost his ability to return to being an energy creature, and, even in kat form, his mind still functions like a computer. With these abilities he was able to maintain a mental link to Dark Kat's computer systems and instantaneously carry out any order

Sypher's downfall as a useful henchman came when he proposed that he return to his energy form and merge with the capture SWAT Kat Razor to take control of the smaller SWAT Kat's body, using him to lure the other SWAT Kat into a trap. Dark Kat was thrilled with the idea of controlling a SWAT Kat against his will and gave his permission. Sypher leapt into Razor... and found that controlling a strong-willed kat when you have essentially no will of your own is not an easy task. Mentally battered when he hit on Razor's memories and their emotional baggage, he found himself lost in the kat. Lost enough that he wasn't sure where he ended and Razor started anymore. Fortunately for him, Razor has a heart big enough to include even enemies invading his mind and offered him a hand in finding his way back out.

The Sypher that accepted the offer, the Sypher that later emerged, was not Dark Kat's puppet. In fact, he was more kat than computer. He turned his back on Dark Kat after a brief battle of wills and left with the SWAT Kats to spend his next twenty-four hours in contemplation and carefully disabling every control Dark Kat had placed in his mind.