Guiltythree
Plot spoiler, maybe. here is my personal hypothesis, casia is aware of the river loop, just like sunny, but she is not using her seer power. Instead, she is keeping journals, and by mentioning a 100 of them means they have repeated this loop a 100 time. but why is she not corrupted? , I would guss sunny gave her the mirror since he made the key so she would just to the next loop uncorrupted , thus torment already down. he used the key and forgot everything about the loop while casia made sure he followed his plan and event sequence. ps the box is made by sunny as well.