The Blood Demon is the thing that is controlling people through the Kamidogu. Havik is confirmed to be controlling people through the Kamidogu. This isn't that obvious in Harpoon's write-up, but it's clear in the comic, because Kuai Liang's speech continues from Havik's mouth once we cut to Havik.
It's like what [MENTION=2722]Snow[/MENTION] said on the last page, the comic takes place 10 years before the game. If Havik succeeds in the comic, how the hell does nobody realize it for 10 years? Why does no one consider him a threat in the trailers? Raiden and Scorpion are both tracking the Kamidogu right now, what, they just give up and stop? Reiko dies, and nobody goes looking for who was helping him? I don't see it. And if Havik doesn't succeed, then he has no basis to be the big bad. So... yeah...