Slender man victim recovering
The unnamed 12-year-old victim's condition has been upgraded to fair, a spokeswoman for Waukesha Memorial Hospital told the Milwaukee Journal Sentinel newspaper on Wednesday.
Police have released the 911 call by the bicyclist who found the 12-year-old, her arms, legs and torso covered in knife wounds as she crawled from the scene of the attack in Waukesha.
Two girls, also 12, were charged on Monday in adult court with attempted homicide.
Prosecutors say the defendants lured their victim into a park on Saturday before repeatedly knifing her. One of the wounds came within a millimetre of piercing a major artery near her heart.
The pair told detectives they had plotted for months to kill the other girl in the hope of winning favour with Slender Man.
Police were told they had planned to run away to the character's mansion, which they believed to be located in Nicolet National Forest, northern Wisconsin.
One of the accused allegedly told a detective: "It was weird that I didn't feel remorse."
Members of her family wept during her court appearance.
Neighbours of the defendants say they are stunned by the allegations.
Emily Edwards, 15, a former babysitter for one of them, told the AP news agency the child had never given any hint of a nasty streak.
"She was completely normal, nothing off about her," the teenager said. "She was very social, friendly, outgoing, which is what makes this whole thing so weird."
Another neighbour, Paul Plotkin, said one of the alleged attackers came from "a normal middle-class family".
"It just goes to show," said Mr Plotkin, 44, "no matter how hard you try to instill good morals, good values, things can still go wrong."
Anthony Cotton, a lawyer for one of the girls, is trying to transfer her case to juvenile court.
He said there would be more social services in that system.
"She's 12 and she has mental health issues," Mr Cotton said. "There's no question that she needs to go to the hospital."
The defendants are due back in court next week and face up to 60 years in jail if convicted.
According to Know Your Meme , which tracks internet trends, Slender Man originated in 2009 during a competition on a web forum to create spooky images.
The mythical creature went viral, and is often depicted as a tall, thin, blank-faced figure wearing a black suit.