Beginning in the near future, humanity has begun to create true AIs and these AIs live and work amongst them. “Vivy” is one of those AIs, created to be a singing entertainer for an amusement park (a “songstress”) and she’s content with her unchanging routine. But then something very un-routine happens, a “virus” enters her system and claims to be a super-advanced AI from the future, sent back in time to enlist her help in changing the present to prevent an AI uprising that will kill all humans. AI can’t lie, and all AI are concerned with the safety of humans to some extent, so Vivy has no choice but to go along with this double-life and participate in the most major, AI-related events for the next hundred years and to see if the Singularity Project was enough to save humanity after all.
Vivy Prototype is an original light novel series but, as contradictory as it sounds, Vivy: Fluorite Eye’s Song is also a wholly original TV anime. Neither is an adaption of the other strictly speaking as Tappei Nagatsuki, the writer of Re:Zero, and Eiji Umehara, the writer of Chaos;Child, teamed up to write this series (alternating volumes) because the idea was that it might be easier to draft an original anime this way instead of the usual methods (somehow). These two volumes correspond to the first three arcs of the anime and while the overall events are the same, small details are different from the get-go and if I had to pick one version over the other it would definitely be the anime.
I’ve noticed over the years that I’m prone to preferring the first medium I saw a story in over all others (which is usually the source material anyway) which probably played a role in why I enjoyed the anime more than these novels but I also just think that the anime staff made smarter choices when it came to Vivy’s characterization and in the world building. In Fluorite Eye’s Vivy starts out as an AI who was an important step in AI development but still only manages to attract a modest crowd at a smaller stage at the theme park where she works, so even if her vocal performance is amazing she’s still just a machine doing a job and that kind of novelty wears off quickly. Her popularity does grow over the course of the series to an extent and that could even be interpreted that, even though she’s not human, the experiences she’s had have influenced her and given her a more complex view of the world that she’s able to channel into her singing and helps to back up her character growth.
In Prototype however, Vivy has remained a very popular attraction at Nialand since her introduction, appears more human-like in her ability to easily converse with the park guests no matter the topic, and immediately accepts Matsumoto which his mission much easier. In Fluorite Eye’s, she’s very suspicious of Matsumoto at the start (and why shouldn’t she be? He’s claiming to be a body-less AI from the future sent to change the past which is not a very rational or logical claim) and it takes a long time for her to warm up to the idea of working with him and the idea of how this will change her “mission,” which is at the heart of all AI programming (in the anime we also explicitly see how AIs can’t handle having multiple missions without this programming completely falling apart, Vivy is wary because it’s her mental stability/existence on the line if this goes badly). In Prototype Vivy’s thought process seems to go “he is an AI and AIs can’t lie, therefore this must be true” and she seems to be lacking some of the caution Flourite Eye’s Vivy had; the early dynamics of Vivy and Matsumoto’s interactions is built around that sense of suspicion so the lack of it (which is possibly a more “robot”-like quality) flattened that relationship.
Prototype Vivy also has a blink and you’ll miss it scene (I had to go back and explicitly try to find it) early on where she decides to separate her memories and keep the part of herself that knows about the Singularity Project distinct from her normal self, for reasons I couldn’t figure out and it definitely has already caused issues for her in-story. A similar event happens to Fluorite Eye’s Vivy about halfway though the series because Vivy is so traumatized by the events at the end of the Metal Float arc that splitting those memories off becomes a kind of self-defense mechanism, not just an arbitrary decision for drama like it plays out in Prototype. These two volumes do cover to the end of the Metal Float arc and a bit past it, which turns out to be necessary since that arc does not end in the same way (specifically, anime Vivy’s traumatic event just does not occur) but that extra bit honestly was rather boring and unneeded. We already knew that there’s significant AI-hate in the world, TOAK is the main villain in both versions after all, and it just feels like a much more stock kind of antagonism than the slightly more nuanced situation in the anime.
Speaking of TOAK, in both versions there’s a particular fighter that Vivy keeps accidentally encountering and his character arc in-progress has been greatly flattened out in Prototype; in Fluorite Eye’s he appears in the first arc and is saved by Vivy almost on instinct (sowing the initial seeds of “am I only the wrong path?”), he’s saved by Estella in the second arc and again by Vivy in the third arc (frankly it’s an impressive number of coincidental encounters for a non-romantic pairing). In Prototype however he makes a very active attempt to kill Vivy and the human she’s helping in the first arc and, perhaps because of that impression, continues to feel like a rather flat, generic antagonist throughout (which will be a problem as this series continues to follow the same rough plot beats and arcs that the anime did).
Even the origin of Vivy’s name is changed between the two versions of the story: in Fluorite Eye’s she’s named “Diva” by her creators from the start (since she was created to be a singer, a “diva”) and it’s one of her few guests who comes up with the nickname “Vivy” that she later adopts (which also gives both her and the viewers more of an emotional attachment to this side character who only appears briefly). In Prototype, she was created without a designation, later nicknamed Vivy by everyone, and after the AI Naming Law passes (as a result of her invention in the first arc) the theme park throws a contest for visitors to name her and that’s where “Diva” comes from. It’s a much more convoluted way to explain why she has two names, making the name that she uses during her missions, Vivy, feel much less impactful, and the fact that the AI Naming Law is in-story supposed to be the first step in granting AIs more rights/autonomy and yet she doesn’t even get to name herself, it’s a name others chosen for her by strangers, sure makes for some strange optics that I’m not sure the creators intended to have.
I didn’t expect to encounter so many differences, large and small, in these light novels but adding them together and I really don’t feel like it works as well as the anime did. Of course, the anime was also helped by having music and visuals to accompany Vivy’s performances and the quickly increasing level of technology, but I truly feel like the anime had a tighter theme and a more focused vision. I almost wonder how much they really needed or used these light novels as a guide! It sounds as if the two versions diverge even more as the story continues on so I don’t see myself picking up the final two volumes in this series unless I become deeply, morbidly curious about it.