The most prominent is Alucard's arc: original Japanese characters Sumi and Taka (brother-sister vampire hunters) train under him, leading to an explicit threesome that confirms his bisexuality in the series, followed immediately by their betrayal and attempt to murder him mid-intimacy using silver restraints; Alucard kills them in self-defense and displays their bodies as a warning. This sequence drives much of his isolation and trauma storyline across multiple episodes.

Additional elements include the lesbian couple Morana and Striga among Carmilla's villainous sisters, and the prominent role of Isaac, a Black forgemaster whose race differs from the source games' depiction of the character. Creator Warren Ellis emphasized philosophical explorations of power, humanity, and betrayal over explicit activism, with diversity framed as organic to a global story.

Audience reactions included backlash over the bisexual reveal tied to trauma and the graphic sex scenes, with some labeling the representation harmful or pandering. These elements influence character arcs and subplots significantly but do not redefine the foundational dark fantasy narrative.