Ultimately, Zhang Yanwei, the ultimate villain died as a free woman. She did not have any feelings of fear or nostalgia. She had even entrusted all of her research materials to Chu Xuan, who she deeply respected a lot.
Chu Xuan may be the only one who actually saw through her from the very beginning. He even attempted to make the rest of the world see it his way. He even attempted to invite Zhang Yanwei to the Endless Squad. To no one's surprise, it was vehemently rejected by the silly captain, Zheng Yi.
To quote Zheng Yi's words, the Endless Squad would never accept scumbags. They would never, ever accept people who would turn on their own kind. Zhang Yanwei was a monster who would throw aside her feelings and treat human life as worthless. How could they accept such a person?