Well, the villain isn't really evil, he has good intentions, but he's determined to be blind to the consequences of his actions. Sort of like someone who wants to produce energy and create jobs, but refuses to believe in climate change because it's, well, inconvenient.
There has to be a sacrifice at the end of the story, but it's just a matter of who and what. I'm hoping to avoid dog and death.
Sacrifice the character the readers love most? Why yes, Joss and Tim have influenced me.
Only if you do it in the most emotionally wrenching way possible.
Whenever there's a cute critter, I'm always certain it's going to die. I've been known to check the last chapter to see if the critter's still there. Killing off the hero's beloved pet seems cheap, anymore.
But I loved the villain going "I *like* dogs." Humanity, not so much.
Villains working with a sense of righteous purpose are the most dangerous. Pure evil can be negotiated with.
Critters in books, yes, often -- I am still mad at The Knife of Never Letting Go for that. Completely unnecessary.
In movies? You want to live? Safest place to stand is next to the dog.
You've never watched Games of Thrones, huh?
I think I've figured out my sacrifice along with most of the plot. I just hope the plot isn't too long to squeeze into a MG wordcount.
Make it a series! Kids LOVE series.