Right... I already clarified that much in the bolded characters. But let me make this SUPER specific so we don't all get hung up on small details.
What I meant to say, is that you don't meet Sephiroth in the flesh (so to speak) until the Junon Boat. I didn't use Kalm as an example because it's a flashback. I'm aware that the teaser trailer is insinuating it's also a flashback, but inserting a flashback at some point in Midgar is shitty writing - and does a piss poor job of setting the stage with Sephiroth as a character/villain.
Well, we can't say it's shitty writing until we actually see it. And for all we know, this is the flashback from Kalm.