"During the battle on Onigashima, black flashes came from Zoro's sword. Does he possess the qualities of a Conqueror!?"
Eh, I don't get the fuss really - just standard Magazine practiced where they don't outright confirm stuff that wasn't point blank stated in the manga.
Yes, we know Zoro has it in the manga from the standard CoC effects and through basic implication. But ig it wasn't stated blatantly enough to be included in the Vivre Cards