Yet the 16-year-old horror enthusiast showed her tender side with her latest work - a feel-good tale in which her fictional self gives a helping hand to scavengers.
The short story won first place in the junior category in this winter's South China Morning Post and RTHK's Top Story competition, sponsored by Samsung and Pan Macmillan.
Vivian is a Form Five student at St Catharine's School for Girls, in Kwun Tong. She often sees five or six scavengers with carts, wandering by the wet market near the school, collecting discarded paper.
"The sad image of a short, old man in his mid-70s with a humpback, salvaging scrap cardboard in the streets, left a deep impression in my mind," Vivian says. "He seemed to lead a lonely, lowly life." In her story, Vivian's fictional self takes over a feeble scavenger's cart and helps to push it uphill.
Such poor people are commonplace in Hong Kong.
Vivian watched television documentaries and read about the poor to gain a broader view of the lives of the impoverished.
The Hong Kong Council of Social Service, which provides welfare for those in need, says most of the scavengers are single people, aged 60 or over, who do not have the support of family members and must survive on a monthly income of between HK$100 and HK$500.
Vivian is critical of members of the public who turn a blind eye to such poor people. She says: "Such old people deserve our respect. They are independent, dignified souls who want to make a living with their own hands."
Vivian learned about storytelling by reading her favourite novel, Good Omens, written jointly by Terry Pratchett and Neil Gaiman. It showed her that a good story needs to be filled with lots of surprises and multidimensional characters - and should never give away the ending.
That's why she added a twist to her story: the scavenger repays her kindness by giving her a little wooden box that can be opened only by someone she loves - her young sister. "Usually we put gifts inside a box," Vivian says. "But this time the present is the box itself. It takes time to realise its value."
This is Vivian's first success in a writing competition, but she often writes stories for her friends and shares her work by posting it on Facebook. Since the summer of 2010, Vivian has been working on a novel, Plan A, about an anti-government group trying to overthrow a dictatorship. The administration's secret agents, who have supernatural powers, join the opposition. But one of them is a spy.
"I was inspired by the anti-government protests, where people wore Guy Fawkes masks," she says. "My story will be complicated, with plots within plots."
Vivian plans to study English at university and hopes her book will be published one day.