He was known as “Hero,” she was “Kitten.” He was the master. She, his online sex servant.

That was the scenario detailed in felony sexual assault charges filed against a Washington state man, Cheyenne Cody Vedaa Foster, 19, who ordered a 13-year-old Stillwater girl to wear a collar proving her commitment to him.

“Kitten is to take any opportunity she can find to show Hero her body and do something naughty for him,” said one of many “Kitten’s Rules” the girl wrote in crayon and posted on her bedroom door, according to the criminal complaint filed Monday in Washington County District Court.

“I’m telling parents to rethink your notions about privacy and boundaries,” County Attorney Pete Orput said Wednesday. It’s not an intrusion, but a necessity, to take charge of children’s use of phones and computers in these days of a “very unsafe” Internet, he said.

In March, a police officer at Stillwater Junior High School learned of “inappropriate communication” between a seventh-grader and a 19-year-old man in Arlington, Wash., the complaint said. After reviewing e-mail correspondence, the officer “believed that this may be a copycat from the character in the novel and movie ‘50 Shades of Grey’ where the dominant male character uses a contract and rules to control a submissive female,” the complaint said.

According to the complaint:

The girl began chatting with Foster on social media sites in December 2014. Eventually they exchanged phone numbers, texted and “FaceTimed, or video chatted, daily. The girl sent nude photos and “said she was in love with the defendant and hoped that once she turned 18, she could run away and be with him forever.”

Foster instructed the girl to abuse herself sexually and commit sex acts while choking herself with fabric until she couldn’t breathe.

The girl responded “that she would like her punishments to ‘kill me,’ ” according to the complaint. “The defendant stated, ‘Maybe one day, baby girl. Every time we FaceTime you’re going to almost commit suicide for Daddy, OK?’ ”

In August, after Foster learned police were investigating, he told the girl he is “old enough to make choices and I made one with you that I should have been more careful about,” according to the complaint. After hearing that she was continuing to choke herself, Foster stopped asking for sexual fetishes, because “if someone found out that I instructed you to do something harmful, even if you asked for it, we’d have even more problems.”

Last week, the girl told Stillwater police that she feared Foster, that he had caused her “physical pain” and that she knew of two other children following his commands.

“Through the investigation, it is believed that the defendant has communicated with other minor children at Stillwater Junior High,” the complaint said.

The girl told police that, at Foster’s direction, she had communicated electronically with other people who take on a “dominant” role and had sent sexually graphic photos to them, the complaint said.

Foster was arrested and extradition is pending, Orput said.