This chapter explores the complex relationship between loneliness and dark personality traits, especially the Dark Tetrad (DT): Machiavellianism, psychopathy, narcissism, and sadistic personality. Individuals who exhibit high levels of DT traits frequently have adverse social perceptions and encounter social exclusion, which can exacerbate feelings of loneliness. Empirical studies demonstrate that loneliness can amplify aggressive behaviors, such as Internet trolling, particularly among those with high DT traits and adverse childhood experiences. However, individuals with high levels of DT traits do not invariably face universal rejection. In specific contexts, such as circumstances involving low self-control, feelings of insecurity, or particular relational needs, these traits may be perceived as attractive or even lead to leadership roles. This paradox—being both socially rejected and selectively sought—highlights the dual social roles that these individuals play. While loneliness has been demonstrated to exacerbate antisocial tendencies, the presence of meaningful relationships has been shown to serve as a mitigating factor in these effects. It is imperative to comprehend the conditions under which individuals with dark traits maintain or lose social ties to address their potential for social dysfunction and to promote healthier interpersonal dynamics.