I'm not entirely sure specifically about 'All his engines Constantine graphic novels'. It could be a very niche or new series. Maybe it's about the character Constantine in a graphic novel setting with some sort of connection to engines? It's hard to say without more context.
It could be the main protagonist if the story is written in a way that the character manages to control and utilize all the Akatsuki powers effectively. With the combined powers, they would have a vast array of abilities at their disposal, making them extremely formidable.
In some comic storylines, Constantine's sexuality is ambiguous or not clearly defined. It depends on the specific interpretation and version of the character.
In some comic storylines, Constantine's sexuality may be explored or depicted in a way that suggests he could be gay, but it's not a consistent or definitive aspect across all of his appearances.
Well, it could be that there's a plot device like an ancient artifact. This artifact might have the power to draw out and combine the Akatsuki powers. The Akatsuki members themselves might be tricked into contributing their powers to this artifact, and then the protagonist or an antagonist gets hold of it and gains all those combined powers. It's a common trope in fanfiction to use such magical or mysterious items to bring about extraordinary power combinations.
One of the best Constantine stories is his battle against powerful demons. He uses his wits and knowledge of the occult to outsmart them. For example, in the story where he faces a horde of demons in an old, abandoned cathedral. He draws magical sigils on the floor to keep them at bay while he figures out a way to banish them back to their realm.