It’s mentioned more than once that love is the strongest emotion, even by geto once he’s defeated; So yuta losing rika, who he so dearly loved and accidentally cursing her caused a perfect storm of … She probably emotionally abused rika, and because she suspects rika killed her son, also blames rika for killing her mother (when she didnt).

Why is it … Ryu calls rika a “big thing” and guesses that rika has her own technique. One of the blatant differences between shikigami and cursed spirits is that cursed spirits can posses their own innate technique. Rika-z is both the soul of rika-o and the curse (rika-n) formed by young yuta. Both the human and the cursed spirit share the same name, but rika-o's generally referred to with her full name to avoid …

Both the human and the cursed spirit share the same name, but rika-o's generally referred to with her full name to avoid …