People can't read, if it was oden's haki (full blast) it'd put deeper cuts in kaido, and then kaido would've realized that and make a comment to confirm it, but it especially says that Enma 'draws haki from the wielder as it's being wielded by its owner', which means, it's zoro's haki being sucked up, hence why he's so drained after using it for strong attacks, I'm sanji fan and even i know it's zoro's haki, yes it's oden's sword, but it's no longer being utilized by him, it has a new owner, oden has nothing to do with enma's current performance, that has to do with zoro now.