To be fair, If the Local Necromancer overload is trying to fight a cult of Evil demon worshipers. It really dose not matter who has the moral high ground. They are still both evil. And considering they couldn't Kill the puppet master. One could argue that this wasn't a curse but an act of desperation to bind them to the trees. Further more, Forbidden place generally means it is Insanely Dangerous rather then Keep out you might see something you shouldn't have. Case in point what happened to the dark aves. As give you any money if brand would have put a wing on that tree. Brand would be just devoured. Only reason roko wasn't was because it can't devour inanimate objects.
Also, just got to be frank hear. Lets give the Quetz the benefit of the doubt hear. As for all we know Every player on the planet fought the puppet master. Sadia just dose not know, as well she wasn't born back then. Regardless if you know anything About evil manipulators. You really should not trust them.
Hell hear is some Examples. Lovecraft, Yep eldritch monsters love to go into your dreams and manipulate you. Much like how the puppet master dose.
The Greater demon Kairos Fateweaver Manipulated the dreams of the advisor to ensure he would be summoned to the mortal realm.
Hell thrall was manipulated by someone entering his dreams in Warcraft 3. Granted this was to try to Prevent Armageddon . But point still stands.
Trusting the puppet master is a terrible idea. As what happens when he gets freed? What if he decides try and consume the world again. As i highly doubt Vimir just wanted a little fight before the dream sequence. No The puppet master devoured their bodies. chances are this is a red flag.
Ps. i also kinda doubt sadia wants to see her Family and entire race get Brutally murdered. So i highly doubt she would be down for an all out war against her mother. Also thinking about it. Destroying the Quetz would also cause the word to die. remember their the ones who cause rain. No rain means drought...So sure you could Kill Vetra and Thunder bro. But then you would have to take over their job or else cause the world to fall apart. As sadly this is what happens when all natural phenomenon is caused by some kind of creature.