There´s no indication that Shingetsu helping her it, was more than a spur in the moment thing. I doubt that Anna would have told her mum and I am not sure that Shingetsu knew what Anna was planning to do, until they were at the pyre. It´s possible that Anna told Shingetsu beforehandand she told Anna´s mum, but there´s nothing backing up that conclusion. Anna´s mum really doesn´t win any mum of the year award but I doubt she would have let the three girls go off on their own, playing with a huge fire and high powered magic. In that case they least she would probably go with them to supervise (and bring a few fire extinguishers), then go "oh you are such a good girl" when the spell succeeds.IOW the trick Shingetsu pulled wasn't something they did for shits and giggles, it was something they did because Anna was already intolerable, and this was one way they might have given her enough that she'd be satisfied. But it backfired, and she demanded more and more and more, and here we are.
Yeah. I am wondering a bit about this Anna is a weak mage thing though. She stayed in the battle for a year and the times she got in trouble was when she went berserk. Ok she had two other mages as backup but it didn´t look like they were fighting as a team much. Also Shisui´s support isn´t worth anything, she regularly noped out or fled unless she thought she has the upper hand. Nene camped for a year, gathering data. You don´t need to be the most awesomest mage ever to win the tournament, you just need to be the last one standing who sniped the second last in the back when she´s exhausted from battle and her Armanox damaged. Or, in case you are ruthless enough, wait out the battle, assassinate the sole other contender in the real world (ok, I assume both would go into real deep hiding at that point) and then show up the next full moon as the sole contender. Also Granbelm isn´t an arena like tournament intent on mimizing every other factor besides personal skill, but a FFA fight in various terrains. If her mum had been more open and they had concentrated on a vable strategy, covering for Anna´s weakness in the raw power department, Anna would have a good shot at victory and I assume it doesn´t matter that much that your magic power is lacking after you claimed the prize. It´s access to all the sealed magic in the world after all.Shingetsu and her mother had no reason whatsoever to treat Anna poorly initially. She wasn't fit to be a mage, but that's why Shingetsu was there in the first place. Problem solved. If Anna had the temperament of her sister all would be well. But she didn't; she wanted to be put first, and would not recognize the fact that she had no magical talent to speak of (and couldn't replicate that trick on her own), and started taking it out on the people around her. That's a problem with her, not with the people around her. The fact they handled that problem poorly made a bad situation worse, but it doesn't make them responsible for the matter.
Weren´t you both talking about little Anna as a kid at first? Like little Anna was already a narcissist etc.Nothing about Anna's behavior is "what kids do." Wanting to be the best mage is something kids do, but assaulting others when they don't toady up isn't. Neither is murdering their parents when they're disappointed.