The sequel of the video game would have Jackie trying to free himself from the Darkness.
The Darkness lied to Jackie about taking him over completely.Hence, the beginning of the sequel would have him still in control of himself.
The Darkness wasn't formed from the shadow before light but is in fact an aspect of Nyarlathotep.The Darkness comics have had previous Lovecraftian influence and given that the dark man is credited as one form of Nyarlathotep and the first recorded Darkness host, it may be that he never was a host but was instead the manifest form. Makes sense that all the info given about the darkness is Abrahamic in origin, since few to no people survive contact with old ones, dependent on setting.
The Darkness killed Doctor Strange.Top Cow used to have a policy that certain crossovers were to be taken as canon. Which meant that characters like Strange who played a signficant role in Top Cow's stories have an alternate version of themselves living in that universe. Strange bumped into Jackie and co. when he sensed the events of First Born were about to happen. The Darkness's taking over an entire city and possesing hosts all over the globe seems like something that should attract Strange's attention. Which means he might have tried to intervene before Jackie did and got killed for it.