Unexpected Humans

At the end of the Queen's Tower level of Demon's Souls, you climb a spiral staircase to a chapel-like area.  It's oddly covered in chairs (perhaps an Almodovar reference?).  Anyways, just before you enter the area, you see a cutscene, where the ancient lord of the tower summons some kind of phantasmic human to fight you, before collapsing from agedness.  The cutscene's actually kind of annoying, since unlike most cutscenes in the game, it's quite long, and you're forced to watch it every time you die and restart from the bottom of the staircase.

Oddly, most times I began to climb the staircase, I would get a notice that a Black Phantom has invaded my world.  A Black Phantom is a human character that has come to try to kill you.  I have only a little experience with them, since Demon's Souls is four years old, and probably not a lot of people are online with me.  The Black Phantoms couldn't seem to get on the staircase with me.  They must not be allowed to interfere with this part of the level.

In any case, the first time I fight the summoned monster I'm destroyed almost instantly - he carries a giant sword and fights extremely well.  The second time he's changed to a smaller sword and shield.  I notice this but don't think much about it, because Demon's Souls requires quite a bit of concentration while you're fighting.  This time he's running around like crazy.  He's not doing a lot of damage, but he's pretty good with that shield, and it's quite difficult to get hits in.  Plus as his health goes down, he starts shooting magic bullets from around his head.  So it's still a pretty challenging fight, although eventually I get him.

When I win, I get a message "The Black Phantom was Slain".  I'm stunned.  That whole time, I've been fighting against a human opponent.  Of course, it's easy to see in retrospect.  There's no reason I shouldn't have guessed, except that the boss just didn't seem like a human opponent.  Sure he was running around like a fool, but he used the same tactics the whole time, even when he was low on health and it was clear that things weren't going well.

I've never confused a human for an AI before.  It's definitely an eerie feeling.