The conclusion of [Oshi no Ko] and Mephisto
The ending theme for the first season of the anime, "Mephisto," was released about a year and a half before the conclusion of the original manga.
However, it shares many similarities with Aqua's death scene in the original manga, suggesting that the song was created with the conclusion in mind.
Furthermore, the ending's final scene fast-forwards from Ai's death, ending with her being reincarnated as Aqua, likely alluding to a "revolving lantern."
The lyrics at that time are "Sleep well, children of the stars. Aim well, children of the stars."

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