Dark Determination (漆黒の意志, Shikkoku no ishi, lit. "Pitch Black Intent") is a phenomenon unique to the JoJo's Bizarre Adventure series, formally introduced in its seventh part, Steel Ball Run.
An antithesis to the Golden Spirit, dark determination is a particular state of mind during which one's resolve and intent to kill rises to the surface. The term itself is coined by Ringo Roadagain[1] and is described by Gyro as one's willing to murder without hesitation and throw away their humanity.[2]
Dark determination is a particular state of mind that reoccurs periodically throughout the later parts of the JoJo's Bizarre Adventure series. As the name suggests, this phenomenon occurs when a character with malicious intentions briefly supersedes their moral compass, during which they are prone to using deadly force to achieve their own personal goals. Anyone with dark intent in their eyes becomes noticeably more ruthless, cold-blooded, and will not hesitate to commit great acts of violence, if not outright murder. Dark determination is most often associated with a protagonist's moral ambiguity and will manifest itself as small flames burning in their irises.
The trigger for dark determination will depend on the individual and the situation at hand but is usually related to the act of protecting, avenging, or acquiring something important. A common example is a friend or loved one in danger, as was the case with Jolyne Cujoh who heard Ermes Costello being mugged by prison guards[3], or Josuke Higashikata seeing Yasuho Hirose being kidnapped by an enemy[4]. In Johnny Joestar's particular case, his dark determination was centered around his goal of obtaining the Saint's Corpse through violence.