I don't think there is a Marvel game equivalent to DCUO. Usually, Marvel games have their own unique features and gameplay mechanics that set them apart.
The Cheval Noir comic has been collected in some cases. However, it depends on the region and the interest of collectors. Sometimes, limited editions or special runs might exist.
You can start by using a limited color palette with darker tones. Also, pay attention to the light sources and create strong contrasts for that noir effect.
One popular DCUO fan fiction could be those that focus on creating new storylines for lesser - known characters. For example, a story about a new sidekick of Batman who has unique powers and has to prove themselves in Gotham. Another type might be crossovers within the DCUO universe, like a story where heroes from different factions have to team up to fight a common, powerful enemy that threatens the entire game world.
The DCUO (DC Universe Online) origin story is mainly about how your character comes into being in the DC Universe. It sets the stage for your adventures. It might involve things like your character getting powers, either through some scientific accident or a magical encounter. It's the starting point that defines who your character is and what their place will be in the world filled with superheroes and villains.
I'm not entirely sure specifically about the 'Chroma Stories' in 'Black Tech Joshua Harris'. It could be some unique narratives related to the use of color or chromatic elements within the context of Joshua Harris's black tech work. Maybe it involves how different colors are used in tech - like in displays, visual interfaces, or even in the branding of his tech projects.
As we don't have much information about Black Joshua Harris Chroma Stories, it could be that the specialness lies in the combination of elements. Maybe Joshua Harris has a unique writing style that blends the idea of 'Black' (whatever it represents in the context) with the chromatic concept of 'Chroma' in a way that creates a whole new world in the stories. It could also be that the stories are told from a very different perspective that makes them stand out, but again, this is all speculation without more details.