Rina was originally shy and easily embarassed, she couldn't let go of her other half. Then with time, Rina slowly became her own self, and chose her own path, joining the Yellow House. Rina wants to be controlled, she craves to be used and be a toy to the harem she's building out of her family members.
Short Story
Rina is born as a human, after Irina Shiverous got split in two half due to a rebirth that occured in Farnese's womb. Since then, she tried to repair her original's errors to the Red House, but got banned and so choose to join the Yellow House instead. She got matched with Carla with who she quickly grew attached to, and started making her own harem after that, giving herself into becoming a slime, and thus, losing her short lived memory to rebirth once again, as a slime. The Passive Alteration made her more confident, curvier, and the body to embodies the mother role she's craving for.