(CNN)It reads like the opening of a dystopian novel: "The Incel Rebellion has already begun!"
The mysterious line actually comes from a message police say the alleged Toronto killer posted on Facebook minutes before the van rampage that left 10 pedestrians dead.
"We will overthrow all the Chads and Stacys!" it continues. "All hail the Supreme Gentleman Elliot Rodger!"
But this is not fiction. The unusual references apparently made by suspect Alek Minassian reflect a real-life online underworld of misogyny and violence that law enforcement officials now are combing for evidence of the motive behind the vehicular carnage.
Here's a glimpse into its dark corners:
What does 'incel' mean?
"Incel" is short for "involuntarily celibate."
It's a movement made up almost entirely of men who claim they "can't have sex despite wanting to," according to incels.me.
Central to incel ideology is the notion that members have been unfairly denied sex by women because they're unattractive or socially awkward. "In practice this goes beyond simply having sex and enters the realm of having no possibility of finding a partner, either to get validation, love, or acceptance from," the site states.
Incels.me's administrator told CNN that the forum does not allow discussion of illegal acts and will ban users who post such comments.
"Make no mistake, we do not condone any kind of violence, we never have and never will. Inceldom is completely UNrelated to violence or misogyny," the administrator said in an email.
"Yes, some users, like in every community, are more extreme than others in their beliefs, but to make a crude hyperbole: When a muslim commits a terrorist act, people don't claim being a muslim equals being a terrorist. Please don't associate two people who claimed being incel, Elliot Rodger and Alek Minassian, as being representative of the whole incel community, because they are not.
"Bottom line is, incel means being unable to get a romantic or sexual partner, it has nothing to do with terrorist acts."
The site, which claims to have about 5,000 members, became a forum for incels after Reddit banned a similar community late last year.
Reddit said in a statement that it banned the community for violating its prohibition on content that calls for violence or physical harm, The New York Times reported.
Who is Elliot Rodger?
Rodger, 22, killed six people and injured 14 others in 2014 in a stabbing, shooting and vehicle rampage near the University of California, Santa Barbara. He later died from an apparent self-inflicted gunshot wound.
In a 107,000-word manifesto called "My Twisted World," Rodger detailed his plan for his "day of retribution." His main theme was his intractable virginity, which he blamed on "the cruelness of women."
Some incels hail Rodger as the martyr of an armed rebellion -- or "beta uprising" -- waged by sexually frustrated incels against the "Chads and Stacys."
Who are 'Chads and Stacys'?
In the group's lingo, "Chads" are sexually satisfied men -- "charismatic, tall, good-looking, confident, muscular" -- according to the incels site. And "Stacys" are attractive women who reject incels.
Like other communities in the misogynistic online "manosphere," incels also use the term "red pill," as popularized by the movie, "The Matrix." To incels, taking the red pill means waking up to a reality in which men -- not women -- are victims of systemic discrimination.
How have outsiders reacted to incels?
A change.org petition launched last summer decried the incel group as "the epicenter for misogyny on Reddit," citing posts encouraging violence against women and advocating rape.
It also pointed out that Rodger was lauded among some of the group's members, including those who called him "Saint Elliot."
Such adulation wasn't universal, though. In response to Rodger's attack, one member of the now-defunct Reddit group posted: "Tbh (to be honest), ... he's the reason we're associated with school shootings."
How have incels reacted to the Toronto attack?
Since Minassian's apparent reference to the subcultural movement emerged after the Toronto attack, some members of the incels site have hailed him as a new hero, a CNN review found.
One person uploaded a picture of Minassian as a profile image and wrote, "The incel revolution has begun." Another wrote: "Alek Minassian. Spread that name, speak of his sacrifice for our cause, worship him for he gave his life for our future."