Is that a world where nobody needs to study or train? Everyone is simply born with some kind of mark (blessing), which gives them all the skills and knowledge they need for a job, be the job farming or being a heroic fighter or wise man? It seems like a dreadful world, to be honest. Not only because of the strict caste system created by the blessings (which would be curses in disguise for the majority of people) but because it means all the people are just chess pieces for whatever gods are granting those marks. I'm not sure even all of those getting powerful marks would be happy in their lives. Where's the sense of achievement? Like the MC who grew up in the boondocks, obviously without any resources, yet he's an ultimate power house at the age of 13, pretty much having done nothing for it.
In this light the behavior of the battle master, who was the one wanting to kick the MC out of the party, was quite natural. None of these folks have any depth whatsoever, after all. She didn't train for years to build a resilient character, able to face the demons and protect the civilians, always mindful of the bigger picture. She simply got a mark and has to act according to it. Then appears a kid who just happened to have a more powerful mark, making her useless in the same party. Just think about it for a second. None in that world has any prospects, any development. They just have the card the heaven gave them, that's it. It's no wonder a lot of people would turn disillusioned and rotten.