How do you decide to include a character if you have other characters similar to them? Or when they feel not complete or appropriate for the story?

Question

I had an idea for 2 siblings, an older brother and a younger sibling. The older one is a somewhat arrogant man, but loves his younger sibling. The younger sibling has a puppet that talks to them or has some form of function to help or mess with them.

Then there's another sibling, who is quite similar to the younger one. However she (presumably female) has many other traits that the younger sibling doesn't. However this feels like it would not work since 2 siblings loving each other, with one being protective of them seems enough. And having another crazy sibling for the older brother to take care of seems too much for him. And not only that, I also don't feel confident since I rarely see any other media with 3 siblings and 2 of them being problematic but the oldest being sane; no, it usually is only 2 siblings, one being sane, one being crazy and problematic. I don't have much courage or confidence to make the girl a sibling and a character. in fact I almost thought of merging the girl and the younger sibling, but I'm at a loss. Any advice?

Answer 1

Central characters need to play a role in the plot. The girl is only needed for the plot if there is something that only she can do (good or bad) to advance the plot, for good or ill.

Perhaps she needs to be rescued, or perhaps she has a skill that can rescue them. Perhaps she is wicked smart, and provides brains and strategy when the brothers are at a loss.

An overarching element of many stories in many genres is "tribe" or "family", the notion that disparate people come together to do something for the common good. The Avengers, each a solo hero in their own right, team up to defeat a great evil; they form a tribe, there is self-sacrifice, there is synergy, meaning the team can accomplish things no individual can accomplish alone.

This is rooted in ancient human psychology, we would not have survived as a species if we were not social, tribal animals. Even today, many people think it is family before all else, or their larger "tribe" before all else, those outside their blood relations they still consider brothers, or compatriots, or their fellow countrymen.

The girl must matter. You can make her somewhat crazy, but you can also add attributes to her crazy that make her useful and critical. For example she has rage issues, but she would (and will) risk her life to save the younger brother from harm. So when the older brother is forced away (say arrested or captured) and the villains seek the younger brother, thinking the girl is no threat, she saves the day.

Otherwise, your instinct is correct -- Eliminate her and fold her crazy into the younger sibling.