Torturing each other has always been the twins’ favorite game.
Until one day Len went too far and accidentally injured Rin in a way that left her paralyzed. Doctors suggested it would be a mercy to just let her die.
How silly.
Just letting Rin live in such a state was a torture beyond anything the twins could previously imagine. Both for herself and for Len who now had to take care of her for the rest of their lives.
So why would the twins ever want to end it?
Their whole lives has now turned into their favorite game.