Kanna is a symbol of purity. In the beginning of the Summer arc, she doesn’t understand anything about the world or the situation she’s in. All she knows is that she hopes she can meet her mother. Without fully understanding the potential consequences of following that dream, her friends Uraha and Ryuuya support her to make sure that dream can become realised. But all the while, they make it their mission to ensure that Kanna doesn’t lose herself to the mission. She had Ryuuya vow to never kill, and Ryuuya does his best to make sure he never breaks that vow, while also ensuring that Kanna never regrets making it either. Uraha and Ryuuya are united in trying to make Kanna happy, but I never thought of her as a spoiled character. Her life was indisputably cruel, so wanting to help her should be natural for the people who love her.
Because of her upbringing, she acts a lot like a child, but like a child she is inevitably very curious about the world. She’s always asking Uraha and Ryuuya questions about what the world is like (their answers often ending up quite different), and she tries her best to face reality without shying away from it. At the very end, after witnessing her mother’s death and knowing what fate awaits her and her friends, she sacrifices everything to ensure their survival. But in the end, it’s all for naught, as her actions bring about a thousand year curse for all of her loved ones, and all future incarnations of herself. Of course, nobody can blame her for this; it is yet another cruel twist of fate. Kanna is ultimately a very tragic character, but it’s nice to imagine that at the very end, she was able to find peace, after all her dreams were realised through Misuzu.