Haven't really seen people really talk about this but regarding SAIKAI's lyrics....

Is it overanalysis to say that some part of Saikai’s lyrics can also fit for the other nursefather/apprentice pairs, and not just ryoshu/araya/rien? This song is just so well written, and I wouldn't rule out the possibility.

The ones I can found are:

“Providing cannot fill an empty cup thirsting for love”**, Matthias and Kira, Matthias thinks he gives everything his childrens asks for, but in reality he has no love for them, hence Kira is so starved for affection.

“If nutrients are what you lack, I will water you with every drop of blood I have”, Callisto and Albina, this is more literal than the others, they forged their own bodies into artworks, pouring every single drop of blood into them.

“We are built to overcome endless mishaps”, Valencina and Lucio, Valencina firmly believes that she will soon overcome her situation and go back to how things were, while Lucio is abused by her under the belief that pushing him more will make him stronger.

"You have shown me that I'm still capable for someone else, that I still bare the same innoncent inside", Rien and Sora, for Rien, no more needs to be said since it's his battle theme, and for Sora, despite being so deeply rooted to the Index's absolute obedience, is a kind person at core and had some positive interaction with the Sinners such as giving the Spiral's code.

"I knew I must step up, You deserve the world and more", Honestly the Pinky is the one I have the most trouble finding, but I think this line is the one that fits the best. Shiomi laments that she can no longer wander the world as a real Pinky should, and despite her bitterness, truly wants both herself and Ryoshu to escape to the world outside. Araya is also the new pinky nursefather and this line is obviously intended for Ryoshu wanting her to live a happy life. As for the "I must step up" part, it fits how Ren refuses to abandon his master until the very end and died because of it.

This song just stirs my heart in all of the right ways. Hearing it against a desolate, ashen background, just made the tragedy of everything in the House of Spiders sink in. It's all gone now, and all that's left standing before you is a broken and empty husk of a man, waiting for it all to end.

I really hope the apprentices will get a better fate in their next lives where they are never entangled in this cruel web to begin with.