The world of science fiction and fantasy is in shock, following news that the daughter of the bestselling late fantasy author Marion Zimmer Bradley has accused her mother of abusing her as a child.

Authors such as John Scalzi, G Willow Wilson and Jim Hines have reacted to the allegations against a woman who had been regarded a pillar of the SFF community with horror. The writer Janni Lee Simner has announced she will be donating her earnings from a story set in a fictional world created by Bradley to an anti-abuse charity.

Moira Greyland, Bradley's daughter, went public with her accusation on the blog of the author Deirdre Saoirse Moen earlier this month, giving Moen permission to quote from an email in which she wrote: "The first time she molested me, I was three. The last time, I was 12, and able to walk away … She was cruel and violent, as well as completely out of her mind sexually. I am not her only victim, nor were her only victims girls."

Greyland is the daughter of Bradley and Walter Breen, who was jailed for child molestation and died in prison. Greyland wrote in her email to Moen: "I put Walter in jail for molesting one boy ... Walter was a serial rapist with many, many, many victims (I named 22 to the cops) but Marion was far, far worse."

SFF fans are reeling at the news. Bradley, who died in 1999, has been a celebrated author, beloved for her take on the Arthurian legend, The Mists of Avalon, which told the story from the perspectives of the women behind the throne, and for the Darkover stories. Set on a planet colonised by humans, the world of Darkover has continued in anthologies written by other authors.

The accusations have already led one of these writers, Janni Lee Simner, to announce that she is donating the royalties and advances she made from her Darkover stories to the anti-abuse charity RAINN. Simner wrote on her blog that "I remain proud of the Darkover stories I've written, and I respect the many fellow writers who also got their start on the pages of MZB's anthologies and in her magazine. MZB played a huge role in many of our careers, and it's not my intention to deny that, or to deny how deeply many readers were touched – and in some cases saved – by MZB's work. But I also can't deny the harm caused by the flawed creator of that work. What I can do is see to it that my having written in her worlds goes towards fighting those same hurts and abuses in the places they're happening now."

Others said they would not be reading Bradley's novels again. The Hugo award-winning author John Scalzi called the allegations "horrific" on Twitter, while the World Fantasy award winner G Willow Wilson said she was "speechless".

"I can forgive artists for falling short of their ideals," she tweeted, "but not for CHILD ABUSE. Will never recommend any of her work again. You can't cover shit in gold leaf and then claim it doesn't stink."

Jim Hines, who received his "very first rejection letter" from Bradley, and who went on to sell stories to to Marion Zimmer Bradley's Fantasy Magazine and to her anthology Sword & Sorceress XXI, wrote on his blog: "I'm proud of those stories. I believe the Sword & Sorceress series was important, and I'm grateful to Bradley for creating it. I believe her magazine helped a lot of new writers, and her books helped countless readers. All of which makes the revelations about Marion Zimmer Bradley protecting a known child rapist and molesting her own daughter and others even more tragic."

Greyland, writing to the Guardian via email, said that she had not spoken out before "because I thought that my mother's fans would be angry with me for saying anything against someone who had championed women's rights and made so many of them feel differently about themselves and their lives. I didn't want to hurt anyone she had helped, so I just kept my mouth shut".

Greyland, a harpist, singer and opera director, said it was now clear to her that "one reason I never said anything is that I regarded her life as being more important than mine: her fame more important, and assuredly the comfort of her fans as more important. Those who knew me, knew the truth about her, but beyond that, it did not matter what she had done to me, as long as her work and her reputation continued."

She hailed the "outpouring of love and support" which has followed her revelations. "What has happened in the past 20 years, apparently, is that rape, child abuse and incest have been enough in the public eye for them to be accepted, and victims and survivors to routinely be believed now, and there are so many survivors among my mother's fans, as well as supporters of survivors and decent people who care about the truth that my mother is now being held to the very standards she wrote about," her email continued.

"I am so glad I spoke out, because on the blog, so many people have shared their OWN stories of abuse and incest and heartbreak. I am going to keep talking about it, if only so that those people who need to share their own stories will do so now."

After Greyland spoke out earlier this month, Deborah J Ross, author and editor of Darkover anthologies, tweeted in response to a question about the claims: "Only half the story is being told. Please be careful about believing sensationalist rumors online."

Ross, who worked with Bradley on Darkover novels, has subsequently apologised for the tweet in a blog calling it "ill-considered".

"I was wrong about the story, and I was wrong to say what I did. I am deeply sorry for the pain I caused," wrote Ross. "I was shocked and appalled by the story as related by Marion's daughter. I had no prior knowledge of any misdeeds by Marion, and it was completely inappropriate for me to comment. Nothing I have said should be taken as a justification or defence of child abuse. As for Walter Breen, like many others, I was misled into believing that he had not acted on his proclivities. When I found out the truth, I was horrified, and I assisted the police in the investigation of the second set of charges that resulted in his incarceration. I ask for your understanding and patience with me for the time it has taken me to respond. I offer the victims my wholehearted support and prayers for healing."

Russell Galen, the literary agent for the Marion Zimmer Bradley Literary Works Trust, which owns the copyrights to the literary works of Marion Zimmer Bradley and which is administered by an outside trustee, said he and the trustee were "aware of the allegations that have been made".

"Marion is deceased and we are not able to ask her about her side of the story, nor do we have any personal knowledge of the events that are being described. All we can say is that during the decades in which we worked with her, we found Marion to be a great friend and enormously kind person. She was much loved by many friends, especially in the literary community where she supported the careers of many writers at considerable personal expense. That's just a statement of fact based on personal knowledge, and is not meant to be a response to these allegations," Galen told the Guardian.