Hey guy. So Sentinel asked me to do this blog spot the other day and I agreed. So you can thank him for this. In short, let's at new characters and when would be the best times to introduce them to a story.
Please note this blog will be talking about Main and Secondary characters, maybe even tertiary, basically characters that can get a background story, in needed. Background characters don't require this much thought. Also, this blog assumes you've already decided/created characters for your story
Do We Need Them
The first question of about if to add a new question is simple...do you need them. No, more accurate would be to ask, does the story need them?
I've talked before about proactive/strong characters, characters who on some level, drive the story forward. Weak or bad characters in this frame of mind, slow the story down, drive it off course or are simply superfluous. If a character does nothing for the story, I can't say why you should introduce them.
Granted if you have a plan for them down the road in another adventures that's a different story.
What Do They Add
The question of what they add is a good one, but another question is what do they do? It makes little sense to add to mentor/superior archetype characters unless it's a situation such as one being supportive and the other being antagonistic.
I can understand instances like the mentor character going off on their own adventures, though I fail to see how one can't just write it that such things don't have to conflict but that is more the writer's choice.
Is it Time
Connected to the prior point, and perhaps the original purpose of this blog, the question of when to introduce a character is not a simple answer. Depending on the situation, on what their purpose in story is, the best time to introduce a character may change. Do they serve as much needed exposition, then at the start or during the situation may be best for tension building. Are they a villain or herald of the upcoming situation, before, at the start, or if the main villain, during the middle or end, may be best for tension.
However, a character that suddenly comes out of nowhere, is not often the best course of action, particularly of they are of major importance to the plot.
When you introduce such a character, is going to affect the pacing and possibly the tension of the story. I would like to say 'introduce them when they are needed' but that's vague, and grossly under implies what that really entails. Instead, I say follow your instincts.
It's not so simple to tell someone when to add their character(s). I have given some ideas of how to chose, but ultimately that's for the writer to decide, and they can decide poorly or not, but such a thing cannot be easily dictated or decided for them. I believe, however, that writers should and should eventually learnt to 'sense' when a character is needed, or the best time to introduce them. So again, follow your instincts, and if you mess up don't worry, we're not afraid to...tell you, you messed up.