First I want to say, if this has already been brought up elsewhere or anything, just don't respond to the topic and let it disappear.
Okay, so I was re-reading 579, and on page 7 on the top, Coby was holding his head saying a single voice is has vanished. I figure that sounds like Aisa in Skypiea, she could tell when people were killed/fainted. It makes me wonder if he was zoning in on Whitebeard or Luffy, as both would be dead/fainted at that point in time.
Anyway, nothing really huge or anything, I just thought it was kind of neat. Since he's already assimilated a Rokushiki move, and now this… So yeah, thoughts? critiques? additions?