The story revolves around Hikaru Takabe, a reclusive teenage girl who is secretly host to a being known as Horizon, in search of an intergalactic murderer intent on killing humanity.

[11] Deb Aoki from About.com said that "7 Billion Needles is a solid and entertaining sci-fi/action read that's well worth a look", and praised the "crisp and straightforward graphic storytelling", but criticized the "unimaginative character designs" saying, "do all Japanese schoolgirls look like siblings, just with different hairstyles?".

"[15] Joseph Luster from Otaku USA said that "there are times that Tadano's artwork comes off as slightly amateurish; awkward poses and angles abound, mostly from human characters.

However, he makes up for it in spades in almost every other area" and noted "the hulking mutations are reminiscent of Akira's Tetsuo [Shima]—organs and appendages spewing and twisting together in a tidal wave of flesh.

It's a beautiful, moving message in a series where so much of the action is centered around fantastical, non-human things", but said that with "powers building up, the final battle turns into this outlandish celestial light show that would be more at home in Dragon Ball rather than a thoughtful sci-fi masterpiece.