The limits of The Darkness's power and ability is unknown, though it does not function at all in strong light, which turns anything it created into dust. Jackie would appear to have some limited foresight, and has, on a few occasions, seen how individuals will die.
More recent comics show Jackie as having the power and ability to generate permanent physical objects (such as water, and the drug known as Nightfall) as well as technically creating "life" in the form of his lover, Elle. He is able to create these things through practice, and the guidance of Professor Kirchner. During this time, Jackie becomes a drug lord his powers and abilities evolve to form the goblin like darklings into larger hulking more malevolent forms. The palace in which he lives is also constructed from the Darkness, and changes and reforms to Jackie's will, allowing him to technically shift through space and time and get to the places he wants to go faster.
Batman. Why? HE'S THE GOD DAMNED BATMAN!!!!!!!!!!!!!
The Fight is in the ruins of Sparta. Kratos has the Blades of Athena, the wings of Iccarus, and Apollo's Bow. Dante has Rebellion, Ebony, and Ivory. Alucard has The Jackal and The Casull with 15 reloads. Shadow Luffy has his Sword.