My impact character turned into a 2nd main character
Hi, so I'm writing a YA fantasy and I already went through the first 6 parts quite smoothly until it was time to choose my MC and her essential counter part. I already knew that I wanted to my protagonist to be the main character with 1st person POV, but I soon realized there were going to be many scenes where she would be separated from the impact character and the reader needs to know what's going on between both of them so I decided to switch between MC 1st pov and Impact 3rd limited pov. However this turns the impact character into a 2nd main character and with two MC's, that leaves no impact character! Would they both be each other's impact character or do I need another?
Simply put, you don't need another impact character. It's your choice.
It's quite common in romance novels to have two POV characters (the romantic leads), each acting as the other's impact character. Usually the female lead is the primary main character, since romances are written for a female readership.
However, the technique is also used in other genres.
Bear in mind that when you are in character A's POV, character A will be looking at character B, and what A observes B doing or saying will have an impact/influence on A. Similarly, when you are writing from character B's POV, B's perception of A's actions and words
will influence B.
If you have two POV characters, you may decide to make one of them your primary main character. This will be the character whose decision (whether or not to change) determines the outcome at the crisis. In other words, while the second POV character may be the main character of his/her own story, that story may not be fully developed.
While it's tricky to do, you can also choose to make each POV character more or less equal. That is, both their change decisions would have determinative effect on the outcome of the story. For instance, if each of them learns from the other and changes in some way that allows both of them to make an essential contribution to the outcome.
If you go that route, I'd suggest you make each character's inner conflict revolve around a different quality. It might be a bit silly, for example, to have them simply switch sides of the same argument. (For instance, if character A chooses selflessness after seeing character B behave selflessly, while character B learns to be selfish after watching character A's selfishness.) To do so, each would somewhat undermine the other's decision.
The guideline is that if one character changes by adopting some quality he sees in the other, the other character will stay steadfast regarding that quality. On the other hand, if one character stays steadfast regarding a quality, the other character will change.