Doctor Norton, an unspeakably lecherous old doctor, personifies the Symantec Norton AntiVirus software. While an ingenious physician, he is infamously known to request (and attempt) the total undressing of an OS-tan for a full physical inspection, even when they're completely healthy. The doctor's lust has no bounds, and his morality is void. His appearance as a Japanese ghost (the whisp of smoke style tail end instead of legs) is a reference to the Norton Ghost system recovery tool.
Trend Micro Virus Buster
A personification of another antivirus software. He is a young boy, with blonde hair who wears a white T-shirt with the words "Trend Micro" on it and red shorts. He wears a red cap backwards, a band-aid on his cheek and carries a blue satchel bag. It seems that he also likes to take a peep at OS-tans' bodies, so-called "virus scan", just like Doctor Norton.
A personification of another antivirus software, but Downloads of this character are rare. Unlike the two antivirus programs above, McAfee Antivirus is a blonde woman, wearing a long red dress. She is occasionally seen wearing a monocle, or period European wear, also in a red-yellow coloring scheme. It seems that both Doctor Norton and Trend Micro welcome her existence, due to her beauty.
Alternate Male OS Characters
Referred to as the "OS-kuns", where "-kun" is the Japanese honorific commonly used informally between males, are counterpart characters of the OS-tans.
XP-kun is large man in his late teens to early 20s, with a very muscular build, wears shackles on his wrists and legs, tattered blue and white clothing not unlike XP-tan's, and several large scars forming the letters "XP" across his chest. His hair is black, and braided into a long ponytail. XP-kun has an aggressive temperment, and is known for not thinking things through.
ME-kun is a unremarkable boy of high-school age wearing a green uniform, a blazer and shorts, of a private academy. Like his female counterpart he has green hair, with the long 'antenna'; but unlike ME-tan, he is often the one in charge of a situation, providing network connections, fixpacks, or reading the Help documentation to the OS-tans.
2k-kun is a rare character, but his appearance and behavior follows the style of 2k-tan, wearing business attire, fashionable reading glasses, and carries a cell-phone.