As for why Rikka invented a ferocious monster like Colossus Nanase, it has not been revealed here, but we can also do a simple analysis. Rikka has the same immortality ability as Kuro, but it is different from Kuro.

She herself does not like this kind of ability. Kuro prefers to let nature take its course, but Rikka has been troubled by her miserable life. As mentioned earlier, Rikka was hospitalized. The reason why she was hospitalized was not because she had any disease, but because she wanted to use scientific methods to solve her special abilities. For this reason, she even did not hesitate to provide her body to the hospital for research.

However, scientific methods still have no solution, so Rikka wants to use these two abilities to achieve the future she wants. And the steel man Nanase can only be regarded as the product of Rikka's ability experiment.

Rikka, like Kuro, has a sympathetic experience, but this does not become a reason for her to be forgiven. Regardless, the Cyborg Nanase she created had a bad influence on ordinary people and even killed a police officer. Kuro and Qinzi will definitely not sit idly by and let her continue to develop.

The person who constructed Colossus Nanase was Kuro's cousin Rika Sakuragawa, and she was also the person Kuro had always liked. Cousin Rikka, like Kuro, is a survivor of the family's cruel experiments. Therefore, like Kuro, she also has the regeneration ability of "mermaid" and the ability of "pieces" to determine the future.

Guide for Colossus Nanase:

There are two key factors for conquering Colossus Nanase. One is Kotoko’s fictional reasoning ability, which can be used to create stories that netizens can identify with. A new story that pits against the current version of Colossus Nanase is also providing Kuro with a future he can grab onto. The second factor is Kuro's "ability to determine the future."

Through the story constructed by Kotoko, the trend of the Colossus Nanase incident develops in the direction of eliminating Colossus Nanase. At the end of this chapter, the steel man Nanase appears, and the strategy will officially begin. The confrontation with Colossus Nanase is actually the confrontation between Kotoko's fictional story and the legend of Colossus Nanase that has been recognized by the majority of netizens, as well as the confrontation between Kuro's ability to determine the future and his cousin Rikka's ability to determine the future.