It's unrelated to Black Metal, hence the name Unblack Metal. Just doesn't make any sense to me... it may be metal but it is certainly not Black Metal (the style goes against every single principle of what Black Metal is, it's just like Christians messing with Pagan rituals. They still want to keep profaning what is ours after 2000 years of sacrilege)!
Or maybe they just want to play metal and by chance it sounds just like Black Metal, who knows (still not Black Metal for me)...