There's nothing I like better than when a strong and quirky character comes along and takes over my story.
It always seems to rejuvenate me. Brings the story to life. This is a character I like! This character is interesting! I wonder where he or she will take me!
In this case, I've got a couple, which by bringing into the story means that I have to go back and rewrite some of the earlier relationships, but I think it will be worth it.
I worry a little that I've got too many viewpoint characters. I'm not sure what the rule on that is. (Whatever, George R.R. Martin has millions of characters. But then, he is George R.R. Martin.)
I've become very open to detours and derailments. They lead to interesting places.
12 hours ago