Final answer:
The lack of feelings of guilt or remorse over serial violence is characteristic of psychopathy, a personality disorder that includes antisocial behaviors, manipulation, deceit, and a lack of empathy.
Step-by-step explanation:
The characteristic of an offender's lack of feelings of guilt or remorse over serial violence committed against innocent people is most commonly associated with psychopathy. Individuals with psychopathic traits generally show a persistent pattern of disregard for the rights and feelings of others. They often fail to feel guilt or remorse, even after committing serious offenses. Psychopathy is a personality disorder that encompasses a variety of antisocial behaviors, including manipulation, deceit, and a lack of empathy.
While sadism involves deriving pleasure from inflicting pain on others, and narcissism involves an inflated sense of self-importance and a need for admiration, these do not necessarily include the lack of guilt or remorse seen in psychopathy. Similarly, voyeurism is a disorder involving spying on others in private moments, which is distinct from concerns of violence and remorselessness. None of the issues presented in options (c) and (d) of the additional information provided directly correspond with the characteristic traits of a psychopath.