Today Soumatou (the author) posted a Q&A for Kuro on their blog.
Link to the original: http://somatoblog.blog31.fc2.com/blog-entry-530.html
Translation below.
Today, "Kuro", serialized in Tonari Young Jump, has welcomed it's final chapter.
Thanks for staying with it during these 5 years!
So.
Seeing as I never released supplementary materials for "Kuro" at all, the other day I invited people to submit questions about the characters and story on twitter. I received several so I'll answer them here.
- How did the monsters first appear?
The clarification about this world where monsters exist ended up being distant from the main topic (Coco and Kuro's daily life) so, while there's a setting for it, it was omitted from the story. I'll leave that to people's imagination.
- Can Coco not see the blood (body fluids) coming out of the monsters either? (reference to chapter 53-54)
She can't see them. There's a sensation similar to rain though.
- The various "abilities" Kuro can use, can other monsters use them too?
For the most part they can't. Kuro became that sort of specimen through unusual conditions, so it is in various ways special.
- Is draining color essential to Kuro's survival?
In the episodes where there's such a description, it was necessary to a certain extent.
- Will Coco, who didn't take the "shot" be able to interact with monsters from now on?
Please read until the last chapter.
- During the final scenes, did the monster Kuro have hostile intentions?
Chapters 164-186 in particular ended up being written with the intent of messing with the reader, but if you read through them again there are plenty of hints that will let you understand. I went and made them in an unkind way thinking I wanted the readers to find the answer. It might be hard to understand but, if you look at it attentively, you'll surely be able to find the border between reality and the mental landscape as well as Kuro's real intentions.
- Can the "possessed animals" cross the white lines by flying over them or traveling underground?
Like it can be seen in chapter 123, it is possible. But unlike the adult organisms, "black monsters", "possessed animals" are weak to the point a child like Maria can crush them underfoot, so they don't pose a particular threat to people.
Unless you read thoroughly, it's hard to really understand the monsters' ecology, isn't it...
I have the memo I wrote down when creating the story so I'll post it here.