I AGREE 100%? through the whole series it's constantly shown that very quickly, they grew very close, and they teach each other really important things or remind each other of valuable things they forgot along the way

asirpa helps sugimoto bond with nature and see life and death in a different way; he's still super prone to violence and murder, but not as much as in the beginning thanks to her influence? when sugimoto kills, a part of his soul dies a little (his eyes go super dull for example? there was also the whole experience with the deer) and asirpa realizes that

sugimoto helps asirpa learn to rely on others again; after what she went through with her dad and then retar a little bit after, she did her best to become completely self sufficient and wasn't super thrilled about the idea of opening up to people outside of what she has left in her family until sugimoto took her on his trip, meeting a lot of valuable friends in the way