Hecuba is a demon who serves Genma Lord Fortinbras in the game Onimusha. She first appears disguised as the handmaiden Nui. Later, after capturing the boy Yumemaru for her Lord Fortinbras, she reveals her demonic insect form to the protagonist Samanosuke before erecting a demon door to hinder his progress. She is last found in a secluded tower on the castle grounds, tending to her demonic children, before she is slain by Samanosuke.
Hecuba later reappears as a non-playable boss in Onimusha: Blade Warriors.
Hecuba can disguise herself as a human woman with no visable distinguishing marks. In her true wasp-like demon form she can fly as well as lay eggs which hatch into ant-like demon soldiers. In Onimusha she primarily attacks Samanosuke by swiping him with her blade-like limbs and by summoning ant demons.