Robert Walton and Victor Frankenstein and the monster
All three of these guys are driven to explore the world around them; all three of them are super into having dude friends. But there are some crucial differences:
Like Victor, Robert is driven to explore the world. Like the monster, he's utterly alone and friendless. It's almost as if he's the metaphorical link between the two, which is appropriate since he's the literal link between them at the end.
But Robert isn't exactly like Victor, either. While Victor's explorative tendency leads him to self-destruction and death, Walton chooses to cut short his search for knowledge in favor of life —both his and his crew's. But Victor? He sacrifices his entire circle of loved ones for the greater good, first of science, and later of humanity. Heavy stuff.