I'm not sure specifically as I haven't read it in detail. But generally, a light novel often contains elements like unique characters, a fictional world, and an engaging plot. It might be about the relationship between the 'shiro seijo' (white saint) and the 'kuro bokushi' (black priest).
First, check out your local library. They might have it in their collection, especially if they have a section for international or genre - specific literature. If not, then as mentioned before, online retailers are your best bet. You can also try reaching out to light novel fan communities. They might be able to direct you to where you can find it, whether it's a small - scale online store that focuses on rare or imported light novels or a physical store in a particular area known for stocking such items.
Kuro remains alive throughout the Haikyuu manga. The plot doesn't take such a tragic turn for this character. Instead, it emphasizes the team's journey and their passion for volleyball.