My main character who is a rogue and incapable to shift is thinking back to the time when all her pack was killed brutally by a tyrant alpha. All of them set on fire or killed with claws and stuff. The plot is set in a time where wolves live in their territories within a forest. It isn't something modern. I just need help writing the scenario where she is remembering all the bloodshed. I want to explain the scenes she saw. Any ideas?
First, ignore what "they" say about No Prologues. Trad published books are full of them. Second, pay attention to how they should be approached. Usually, a prologue is from the POV of a character other than the main protagonist, and sets up a situation that will affect the protagonist later on. Or it can be from the POV of the protag when he or she is much younger. With that approach, you show the experience as it would have hit her as she was at the time. No reflection, no "I understand it all now." Not in the prologue. Save it for later. The value in either approach is that now the reader knows something the protag doesn't. The full implications need to hit home later in the plot. In your case, you can show the massacre from the POV of an omniscient narrator, and have this eye-in-the-sky make note of the lone young wolf (you are talking wolves?) fleeing into the forest. Or it could be through the eyes of a mother, father, or other guardian shifter, who is relieved to see her escape just as the vicious alpha goes for its jugular. Then in Chapter 1, you switch to your protag's POV, with her living the action in 1st person or close 3rd. What I would not do is have her "remembering" the ordeal in the prologue. If you do that, it should be Chapter 1. I'm curious, though. You say your character is unable to shift. I don't know the rules of these things, but is she stuck as a wolf or as a human?
I think it's important to bear in mind what the prologue is for. The prologue should help the reader understand the novel, not the other way around. It can give some backstory, set the scene, introduce the reader to the overall tone on the book, foreshadow events, and/or introduce some of the characters. I'd think about what the reader might be confused about, or just not get, in the first few pages of chapter 1. That's what the prologue should be about.