Kazuma Ishimaru
Well if we go by Dissidia Zero, his name is pronounced Zi-dahn. (that's a short "i" sound like "zipper" and a short "o" like the word "on")
Kazuma, stop confusing me! I went crazy Googling "Dissidia Zero" just now ("Is it an international version? the Ultimania? Why have I not heard of this?") before I realized what you meant. stare
...But yeah, it is Zi-dahn.