He, Killua P. E. K., Was born in darkness and grew up in darkness. He could not restrain his yearning for light in his heart and approached the sun-like boy at all costs, even if he was burned.
She, Shadow Kures, was forced to bear the shadow behind the light, but she shone brightly under the huge night. If Jay Fulis is the sun that illuminates Killua's life, she is the moon in the threshold that coexists with Killua in the darkness, but keeps him from going astray.