It needs to be a distinctly new power. Something we haven’t seen in game or lore before (Stasis didn’t exist before the inception of Beyond Light. While we saw it with Eris Morne in Shadowkeep, we did not know it was stasis, and Bungie had been making Beyond Light at that point) So, this knocks out Big contenders for new elements, like Resonance, Hive Magic, and Poison. Furthermore, the power needs to be focused on the creation of physical and intractable objects. Tangles, Stasis Crystals, Grapples, and other such objects that interact with the environment. This again, limits subclasses like a Hive Magic and Poison subclass (Wells of Radiance, Bubbles, and other such objects, while creating an environmental effect, do not directly interact with the game environment. The only intractable object I can think of on light subclasses off the top of my head are the Axes and Twilight Arsenal, but that’s the exception, and not the norm.) Lastly, this subclass needs to be of either a Dark Red color, or a pale yellow color, both of which we have already seen darkness powers of, being Resonance and Nightmares. While I do not think we will get those two powers as a darkness subclass, I do think we will get something related to them and their respective color. Bungie is really keen on Color theory, and by extension, the meaning and relationship each color has with the others of its group. Honestly, I couldn’t create a new subclass, but I do know what the parameters of this new Darkness subclass should it ever be made. Of course, there is always room for Bungie to mix it up, and break the chain, but I don’t think they would do that, as it might upset more lore oriented players, who are often your most dedicated bunch.