ANSWERED. Female cultivator transmigrates into a young girl's body when her tribulation goes awry. She inherits the family title and has to go govern a town, later enters a military school, and then becomes a commander in the military. They fight the demon armies. The military elites use a pendant that is passed down through families to transform to do battle. She rescues ML as a boy on the road. He's actually supernatural and is actually some high ranking person in a cult-like organization that controls the pendants and healing of elites who are injured. He tells her to never use the pendant and she's BA enough to never need too. She makes friends with a dragon that she basically uses like a cargo jet, but he does fight a few times too, lol. She really just wants to work on her cultivation and keeps getting sucked into worldly affairs. Eventually, she rebels against the king. In the end, to truly get some peace and quiet, she sets up her own kingdom in a valley where bandits and mad scientists/magicians live. There is a scene where she helps the ML break through the shields around the base where the bad guys are by triggering her next tribulation!
AHHHH I know I've definitely read this before but I'm not sure which cultivation novel it is. Maybe Unprecedented Pill Refiner: Entitled Ninth Young Lady? One of the chapter names is "World Termination Armor" and I think that's the pendant part you were talking about.
@crayole, Yes! That's it. There are a million similarly plotted and named novels. I even looked at that one, saw the vampire tag, and was like, nope that can't be it. I could kick myself! But by then I'd checked so many, I guess I was getting sloppy. I really don't remember vampires though... Thank you, thank you! I felt like it was the best of the 'transmigrated into an untalented girl with terrible fiance and then face slapped people' novels. In part because it had regular, non-face slapping action adventure happening as well.