Hey there. Allow me to offer my congratulations for joining our tidy fanfiction group on the forum. We always appreciate new authors joining our ranks and I can see you're already off to a rather decent start. I'm a stickler for serious and lighthearted stories, but there is a spot in my heart for whimsical ones as well. Your story is part of the latter category and I'm glad I gave it a shot.
It is interesting you decided to go with Sierra for this prompt and the ''what if'' characterization you implement upon him, while slightly out of character for him as the flyer has no qualms about harming children, and that no doubt expands to abandonment as well, was still fascinating to see. Backstory for a character, especially villain at that, can never be overstated by how important it is not for the universe as a whole, but for the fanbase as well. While the idea is not my cup of tea, there's a certain level of creativity and innovation you put into this story from start to finish, and for that I applaud you.
As in every story, there are almost always parts that don't make sense or seem too unlikely to happen in real life. My first point was already mentioned in the paragraph above, so I will not go into detail about that. The Berry Valley scene was one that caught my attention in regard to possible continuity errors; I believe it was said that the yellowbellies first entered the aforesaid valley in the 13th film lead by the gang, so this would present certain issues on that. However, this may not be a big issue as it has been a long time since I watched the movie and the point I just made can be completely wrong. Take my words with a grain of salt.

Characterizations are a huge thing for me and I was glad to see that Sierra didn't just become a different person from canon to make this story work, props for that. Though, there were times when his character started to seem a little bit incorrect when dealing with the hatchling. One last piece of advice before I close this review, I noticed that you changed the story's title at least once and I'd advise you to pick one name and just stick with it, even if you disagree with it later as this can confuse people. I'm also a fan of one-shot stories, which basically in this situation means that I would've liked to see this as one story, not individual chapters. But it worked fine in the end, and that's what matters.
Your writing style is already rather polished and with more experience, you'll soar into highs at a good pace. For now, this was a good story that explored a well written villain involved in a very unique situation. additionally, don't worry too much about not being able to post this story to FFN. Just be sure to check you cross post it eventually as that is required. Good job.
