I've been working on my pet project a lot over the last six months, and I thought I had most of the kinks worked out- but I think I found a problem with my most important character.
The story has a very limited cast of characters- 2 MCs, 3 supporting characters, and then the background characters. All of my primary characters have arcs that are relevent to the plot and theme, and to the story of each of the MCs, and all the characters get some focus over the course of the story. The problem is that the supporting character who introduces the MCs so the plot can happen does pretty much nothing after making that introduction- he isn't present for large portions of the story because of this (he actually has the smallest presence of all the primary characters).
If I didn't need him, I'd cut the character out of the story, since for the most part he wouldn't be missed at all- I can't do this though because I need him for the story to happen to begin with, as well as to help round out the theme and the world, and because of his importance to the main characters (he's responsible for a lot of the conflict and one of the MC's backstory and motivation). I would try combining him with another character, except I don't have any that I can do that with. If either of my other supporting characters got as little spotlight time as him, I don't think there would be a problem, but they don't.
Is having an important character with such a small role workable? What could I do to feature him in the story more?
Edit: The story starts with one of the MCs discovering the problem that drives the plot. The supporting character in question comes to help her, but is really less than interested than being responsible for solving the problem, so he introduces her to the second MC, who takes on the responsability instead (even though he doesn't want to and really shouldn't). The supporting character who introduced the MCs has a short arc that shows up in some spots during the course of the story that ends with him taking over the problem and his responsability for solving it. Aside from his appearances at the beginning and end of the story though, he really doesn't show up much.