GIANT character spoiler below.
Not explicitly. To me, Helen is a bit of a tragic figure. She grew up with violent desires and took them out on animals as a child but eventually managed to repress those urges. One day, however, she gets arrested for some tax irregularity and gets sentenced to time in prison. But rather than going to a nice cozy prison, she’s mistakenly sent to a hardcore prison where she experiences, well, bad things. This reignites her old desires and so one day she decides to act them out - but not with the intention of killing. She poisons Schmidt but is unaware of his allergies and the poison causes a violent bleeding, which ends up killing Schmidt. It’s a course she’s been on before - poisoning people to see what happened - but now that she’s gotten away with murder, something inside her wants to explore that further still. Helen probably has some feelings for Janus - she’s certainly sad that she killed Schmidt, whom Janus seemed to like. She’s basically a budding serial killer being adopted by Janus.