In one of my sections of Aurora Rescue, the one titled "Chimney Rock", I introduced the character of the dog, Hunter. Hunter took an instant liking to one of my main characters, Marty, and chose to stick close to her rather than to his grumpy and demanding mistress, Maggie.
When it was time to leave this section, I originally planned to leave Hunter with Maggie. Hunter is her dog. But, one of my readers wanted to know, "What about Hunter? When am I going see Hunter again?"
So, I checked with my readers, and my technical expert, ol' Buck, my husband, and the decision was made to have Hunter continue in the book. In fact, one of my readers gave me an excellent idea for Hunter in Book Two, which is tentatively titled Aurora Rebound. So, Hunter has joined the cast of continuous characters (as opposed to my scene-specific characters).
After all, he really is a cute dog.