Let me tell you why that’s wrong
The song presents an allegory on human nature. The blind man is a “yes man,” someone who will say anything to make people happy. On the surface, it makes everyone happier, but in reality giving people whatever they want has consequences. For the sake of the story, his life is at stake upon each request. Someone who who couldn’t make everyone happy would feel tortured on the inside that they couldn’t, and that is how it’s represented in the song. He also tells the girl that killing one is no different than two or three. Again, it makes a person feel better, but has dire consequences.
The girl is an example of a know it all. The song is told from her perspective, so we never know what the blind man is thinking. We know the girl talks a lot about him, but there is no guarantee that what she says about the blind man is actually true. He never asked her to protect him, let alone kill for him. He merely pointed in the direction of “enemies” (a word defined by the girl) and she chose to kill them.
So, what’s the moral of the story?
You can’t be either of those people. Yes, it may work out for a while, as shown by the formation of an “impregnable castle.” Yet one shot from the beginning video denies it all.
The girl’s signature knife lying next to a skeleton, her skeleton. The knife is clearly important to the song, being the climax of the story and being featured in the Hero no Jouken picture. The knife was not drawn there for no reason; it shows that the girl died. She died because her lifestyle was unsustainable. This does not mean that all know-it-alls will die, but symbolically shows that the attitude will fail you in the end.
Game theory: the castle became the ark from “ark for the two of us.”
The way they describe the legends of both spreading is eerily similar.
And now the part you can skip: a personal anecdote about why I love this song:
I have two reasons for loving this song.
The first is simple. I share traits with the main characters in the song: I am almost legally blind and I can’t walk properly to some extent because of a few knee surgeries. So of course, when you’re bed-bound after your third surgery you can’t help but feel useless and alone. This song helped me through a hard part of my life, by showing me that even those at a disadvantage can still function fine.
The other reason is another robotics story. I joined the team with my friend. After one year, the Head of Manufacturing and the Head of Design graduated and we were left with no one to build the robot. So in that year, me and my friend came to be known as the dynamic duo: he could see a design in his head and make it in CAD (design software), and I could build anything. Stories spread about the guy who would go without sleep for days to crank out designs and the guy who was faster than the computer-controlled machine. Even two years later, after overcoming many obstacles (like killing obstacles, just not killing them) we still held the team together.
In the face of adversity, you can overcome any challenge.