Definitely. Bruce Banner's transformation into the Hulk was the starting point of the entire concept. The comic storylines have always centered around this original transformation and its consequences.
Bruce Banner became the Hulk after a catastrophic gamma radiation incident during one of his experiments. The radiation altered his genetic makeup, causing him to turn into the Hulk whenever his emotional state becomes intense, mainly anger.
Bruce Banner is still alive in the comics. His storylines have many ups and downs, but death hasn't been the ultimate fate for him. He keeps coming back stronger.
The separation of the Hulk and Banner varies in Marvel comics. Sometimes, external forces or internal conflicts cause them to split, but it's not a consistent occurrence throughout all comics.
Perhaps in a fanfiction, Bruce Banner discovers a new form of science that can enhance Thor's powers even more. Thor, in turn, helps Bruce understand the Asgardian view of the universe, which gives Bruce new insights into his own work. This could lead to a series of events where they team up against a common enemy that is a threat to both Earth and Asgard.
Occasionally, Hulk can take control of Banner. This often happens during intense emotional or physical stress situations. Different comic arcs handle this differently, but it's a common theme.
Yes. The merging of Hulk and Banner in the comics occurs in specific storylines. It's a significant event that changes the character's trajectory and adds depth to their narrative.