Kozue's father was Via, a fallen angel who was not only incredibly powerful, but was also known for being completely unhinged and, perhaps even more importantly, ruthlessly cruel. His reputation alone was enough to make people cautious whenever his name came up, and after everything Kouhei had already experienced, learning that someone like Via was Kozue's father made the situation feel considerably more complicated than it had been a few minutes earlier.
Kouhei was completely speechless after hearing that revelation, so much so that he simply went silent for several moments. There were plenty of things he had expected Yuuna to tell him, but hearing that Kozue's father was a powerful fallen angel who was both unstable and ruthless was definitely nowhere near the top of that list. Honestly, anyone would have been shocked after hearing something like that.
