User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-1758220-20140128014305/@comment-1758220-20140129231918

And I have no idea why they chose to label it Black in Japanese. Regardless, there is already a precedent for Campcom America not to directly follow the Japanese title. And even if they choose an adjective that implies shadowiness/darkness/death/whatever, anything like Obsidian, Jet, Black, etc. which make reference to a blatantly non-existant clour on the monster's body is extremely unlikely.