Rina seems to be friendlier than you, while Rana doesn't seem to like you very much so she will push you a lot more in training, every time you fail in any of the activities Rana will drain your size using magic, making you shrink a little and that will make Rina and Rena grow with their size drain. Every time you end up dying while training, you will return to the moment you met them, but you will be reduced in size and they will not remember you.