What's the best way to grind rapport? I can get 30-40 easy just rushing the first few bosses, but by level 15-16 I'm lucky to get 4 rapport from the last desert boss, and I don't dare try and take my rank Cs into the forest with all that AOE and skill disable spam.
Its easier to grind mass rapport when you are a higher level pretty much since you can skip to different bosses for more rapport, you just have to make do getting 2-4 rapport for now where you currently are at. Despite being C rank just bring a strong friend and healer and you should be fine to progress the story with your party, keep one of your main units in the party as well if you want to be safe. I've been grinding rapport with B and C units and they survive just fine at obsidian mountain while i slowly progress the story.