The sadistic smugness didn't go unnoticed, just like the lack of remorse for killing his rapists companions came through loud and clear. This definitely gave more fuel to his intial concerns about escalation, Helix was clearly capable of extreme violence and this in itself made him all the more determined to ensure it wouldn't happen. Without a background check to go on and Acumen's blatant disregard of circumstances Reid didn't have much to on on aside from this very conversation and whatever he'd gleaned from their previous encounter, which made the whole profiling process a little trickier.
Revised assessment: sociopathic tendencies but not displaying a complete lack of empathy. Most sociopaths that choose a partner showed more obsessive and possessive behavior towards him or her, but based only on this relatively short conversation Helix was more than capable of feeling enough empathy and emotional awareness to not demand that his partner stay with him. A real sociopath would never have willingly let someone go, simply because they couldn't understand how that person could be harmed by their actions.
In this, Helix was the complete opposite.
Abuse victim, definitely, both long term and with a recent event that triggered the violent tendencies. He himself claimed that he'd tried to do the right thing and lay low, "play nice" and that statement seemed genuine, even more so since he hadn't failed until the stressor hit. Most serial killers or rapists that try to stop themselves fail without outside influence, but in Helix's case it was a genuine act of self-preserverance and revenge. A conscious decision triggered by a specific event, rather than a mindless compulsion. The blatant bloodlust after killing the vigilantes was definitely cause for concern, it could easily turn into an addiction but something told him that wasn't the first time this boy had taken a life. Not even close.
By now Reid was getting a pretty good picture of what this kid was all about, and once again he landed in his original conclusion. It wasn't too late, with the right influence Helix could very well turn his life around and find alternative means to keep himself occupied. It wouldn't be easy by any means but if he could just get him to take that chance...
"I'm sorry."
The response was soft, emotion behind it genuine. Perhaps not what Helix expected to hear after all that, but someone should say it. Even if they had nothing to do with everything that had ever happened in this kids life.