Why would it need to influence them?
You play one of the many recently deceased victims of the vampires to be resurrected by the Elder God, as it did for Mobius in Defiance; and you aren't the only one, countless others have also been resurrected. The Elder God has proven to not be omniscient, so it might not anticipate Kain's return to this era. If it doesn't forsee Kain then why would it need to go through the trouble of establishing influence over all of the humans it raises. There already is ample motivation for you and the others, vengeance against the vamps and the promise of a second chance at life once it is over; and as stated before, all you have to do is die once in order for the Elder God to own you once again.