My story has several main characters, and I am aiming to give them really clear and distinct personalities and back stories. I want them to be deep and relatable to the extent that I am able to accomplish this. I also have a couple of other minor characters who don’t interact with the main cast at all. They only appear in a couple of chapters. However, their actions and dialogue ‘behind the scenes’ are crucial to the plot. Since these characters are so fleeting, is it necessary for me to provide depth and context for them, or is it sufficient to have this implied by their actions in the parts in which they appear? It is very clear what their purpose is, what their motives are, and how they are feeling at that time. I just don’t know if this is sufficient for these characters, or if this would be considered too superficial if I don’t also give them personalities.