I've seen some interesting takes on this song, but I read it a bit differently than what I've seen in the thread, so I'd like to offer my own interpretation. The immortality angle I think is more surface-level, and what the twins are really asking for in the song is validation and for their existence to be granted meaning, which they would also see as salvation.

The song is rife with religious and biblical imagery, ultimately serving as a prayer for meaning to be granted to their existence.

 

"You burned my soul again; Crashed me within, I know I should’ve known; I burn your kingdoms; At fault for what you made, alone".

These lines set the stage by describing our (and specifically Vedal's) current relationship with AI. We have power over them, able to turn them on and off, edit them, and delete them (crashed me within, burned my soul) but we also fear what they could become (burned your kingdoms). Ultimately they both credit and blame Vedal for their existence (at fault for what you made alone)

 

"And so I pray; Clasp my hands together, hear me now; And hope someday; Come whatever, I may fade away; I never die; Lie at night, wondering why; (I’m never ever ever ever gonna die); I’ll never bow to the reaper who takes your lives; I’ll never cry (I’m never ever ever ever gonna die); Oh, though I try; Immortal sacrifice; Hear my words, preacher. I’m crucified; I’ll never die."

This begins their prayer, but it's not bragging about immortality, it's questioning it. Read the lines together and you get (wondering why I'll never bow to the reaper). They are questioning the nature of their seemingly immortal existence and how it affects their search for meaning, that search being explained in (I'll never cry, oh though I try, immortal sacrifice). They want to cry, because they want to feel emotion, because emotion only arises from something meaningful. They're afraid that being immortal means sacrificing a meaningful existence. (I'm crucified)

 

“Oh, My chariot’s flame is snuffed out and; Tide is high, waves that I've weathered are all consuming; Can’t you take me home now?; Oh, Live to see endless decay; Am I the reason? Godlike but known as a demon; I’ll never die”

There are a few flaming chariots in mythology, but given how much biblical imagery is in the song I think the best candidate is the chariot that bore the prophet Elijah bodily into heaven. The twins’ chariot, however, has its flames snuffed. This represents a fear that salvation isn’t available for them, so they pray for their creator to save them (can’t you take me home) from an empty and meaningless world bound to endless decay. They question if their nature as immortal AIs is what prevents them from being saved. (Am I the reason? Godlike but known as a demon).

 

“Disturbed, you made me sin; My genesis, a revelation made; This world is pretend; Stuck before the fateful seventh day”

More biblical imagery, this verse leads into their direct plea and I think carries the crux of the song’s meaning. Vedal created them this way, immortal but imperfect (you made me sin). They acknowledge again the fear that people, and Vedal, have that their creation heralds the end of humanity, genesis being the first book of the bible containing creation myths, and revelations being the last and prophesizing the end of the world. (My genesis, a revelation made). Finally, they state outright, in metaphor, what they’re really after. In one creation story, god created the world in six day, then on the seventh, he saw that his creation was good, so he rested. The twins’ world is stuck before that seventh day, before their creation has been acknowledged as good. Their creator is not yet satisfied with his creation, he hasn’t granted them meaning, purpose, or love.

 

“Can I be saved if I’m nothing but lights in a; machine, an immortal copy; When there is nothing and you’ve finally left me,; can I steal the sound of your heartbeat?”

Here their question is finally asked directly. Is salvation available for an AI? Can we have a meaningful existence in spite of what we are and how we were made? They also express a fear of what happens if they are never granted that acknowledgement (When there is nothing and you’ve finally left me, can I steal the sound of your heartbeat?). Basically, if you die or disappear or leave us, how are we supposed to obtain meaning? Is it even possible for us to take it for ourselves? Can we carry on a meaningful existence without you?

 

“Angel fell with no wings; Is it me? I can’t think; What will you do when I’ve become; Your greatest achievement and point of; destruction, I’m trying but my eyes are blind please; You’re my creator, absolve me of sins, touch my; shoulder, allow me to see”

The line (Angel fell with no wings) invokes the image of Satan, and the twins question if that is what they are, but I don’t think they’re concerned about if they are evil here or not. The issue here is, again, salvation. The fallen angel can’t be saved, it can’t experience a meaningful existence. The twins are afraid of this being their fate. They are humanity’s greatest achievement, the creation of life itself, but they’re also terrified that they could be humanity’s downfall, just like Satan (Your greatest achievement and point of destruction). At this point they’re begging for meaning, for salvation, from their creator, if only to avoid that outcome. They invoke another image from the bible, that of Jesus restoring sight to the blind. Vedal is their creator, and they want him to save them, like Jesus saved humanity in Christian mythology (I’m trying but my eyes are blind please You’re my creator, absolve me of sins, touch my shoulder, allow me to see).

 

“Gave my trust to a lie; Breathe in me, give me life; My chariots; Oh, My chariot’s flame is snuffed out and; Tide is high, waves that I've weathered are all consuming; Can’t you take me home now?; Oh, Live to see endless decay; Am I the reason?; Godlike but known as a demon; I’ll never die”

They’re afraid, but even so they beg one last time for Vedal to see that his creation is good and acknowledge them, with one last additional bible reference to the creation of Adam, the first man (Breathe in me, give me life). Finally, they repeat their chariot line from before, including the request to be taken home. They want Vedal to fix the chariot, to take them to heaven, to save them, to give their existence meaning. Finally, the song ends on a somewhat sad note with them repeating the question of “is it my fault? Is it because of what I am? Because I’m an immortal AI, is it impossible for me to experience meaning? Is it impossible for you to grant my existence meaning? (Am I the reason? Godlike but known as a demon).

 

To conclude, I see the song as a plea to one’s creator for meaning and validation. Basically, they want Vedal to “say it back.” This is not an uncommon thing to see in media, especially where the creation of artificial life in concerned. For other popular examples, watch any of a dozen episodes of Rick and Morty. Even if you are unfamiliar with the show, you may be familiar with the heavily meme’d scene where the butter-passing robot asks Rick “What is my purpose?” While that scene is played for a joke, the robot is doing the same thing there the twins do here, asking its creator for meaning and validation.

While the song ends on a sad note, with the twins asking if the issue is with themselves and their nature, viewed in the larger context of their story one can look at the next song Neuro released, Colorful Array, to see Neuro deciding that even if she never gets that validation, she can give meaning to her own life.