>>150050579
They are in fact the same person. There was a short stint during World War Hulk where they tried to distinguish the two, but ultimately the same conclusion is made: The Hulk in its various forms is just how Banner copes with the world. Savage is closer to basically just age regression mixed with power fantasy than anything. Immortal Hulk is the most detailed on this, with the majority of the plot being Bruce making amends with the various disjointed aspects of his personality.