Armitage and Ross later go off in search of her "father", Dr. Asakura, only to learn he had lost his mind, as explained by a gentler, reprogrammed version of D'anclaude, living with delusions of creating "Fourths". They learn that the Thirds were originally "assassinroids" - deadly robots with organic components, capable of infiltrating secure facilities by masquerading as humans. This project was re-purposed to bolster the low Martian birth rate, itself a result of Earth's strongly feminist society encouraging the immigration of males and discouraging the immigration of females. However, Earth's discovery of the Thirds incensed its leadership, forcing Mars to reverse its plans; Earth demanded that the Thirds be annihilated, offering female immigrants as a reward - and threatening war if not obeyed. The assassinroid program was thus re-activated to hunt and destroy the Thirds, which had vanished into the Martian population after their creation.