Fed up after being treated like a perpetual child due to his never-aging body, Sprite used the power of the Dreaming Celestial to hide the legacy of the Eternals and transubstantiate to a human form that would grow older over time. And, in doing so, caused almost all the other Eternals to become dormant, taking on mortal identities.
Sprite himself became the star of a childrens’ TV show – with his appearance on TV leading Ikaris to awaken Makkari and other Eternals. But upon their awakening, Sprite fled, refusing to take responsibility for his actions. Ultimately, Sprite did pay for his deed when he was caught by Zuras, former leader of the Eternals – who executed Sprite for his actions.
Now here's why all this may tell us something about the plot of Eternals. Because Sprite will be played by 12-year-old Lia McHugh, (another gender-swap from comic books), it stands to reason the actor could only play the role once (she's going to get older pretty quick), given never aging from his/her child-like appearance is the entire premise of the character. If McHugh can only play the role once, this lends some support to the idea that Sprite dies.
Add the fact the Eternals have been neither seen not heard from in the MCU up to now, and all put together it could mean Marvel will be borrowing heavily from the Gaiman series - and 12-year-old McHugh could be one of the funkier and more unlikely MCU villains yet.
