
I think I've found the inspiration for Zeon's hair abilities
In Journey to the West, Sun Wukong can transform his hair into some objects, this could be the inspiration behind Zeon making dolls and letters of his hair. And even if Zeon isn't indirectly inspired by Journey to the West, A LOT of East Asian media references this novel, so even if Zeon Hair abilities was inspired by other media, like a cartoon Raiku watched as kid, this media could easily be inspired by this novel.
(Also, offtopic, but is the novel more clear about what is happening if you don't know a lot about Chinese culture? I feel like I'm understand half of what is happening on this series.)