Skull (alternatively romanized as Skarle, or Scar or Scarl in English adaptations) is the title of the field leader of Black Ghost and is alternatively even named Black Ghost by his subordinates at times. He is actually a cyborg with highly advanced cybernetics that surpass all of the 00 series cyborgs, but also became much more of a machine than a human.
- While his name is intended to be read as "Skull", スカール can be alternatively read as "Skarl", "Skal", or "Sekar" (where his equivalent in the graphic novel had his name derived from). This is due to the difficulty that Ishinomori had in rendering "Skull" into katakana, with the ー character being what provides translation confusion. Tokyopop's translation opted to refer to him as "Scar", while the Sony Pictures dub of the 2001 series calls him "Scarl" (based off a translation error seen in some materials where his name is put as "Skarle").