TL;DR
Mewgenics has only five credited character voice roles. Everything else is a giant pool of celebrity and creator cameo recordings that the game assigns to cats at random and pitches up or down. No single cat "is" any single celebrity. If you came looking for a normal cast list where Markiplier voices one specific cat, that list does not exist, and that is by design. Here are the five fixed roles, how the random cameo system works, and which famous names contributed cat vocals.
The five named voice roles
These are the only characters in Mewgenics with a fixed, credited voice. They stay attached to the same character every run.
| Character | Voice |
|---|---|
| Guppy | Edmund McMillen |
| Lucy | Danielle McMillen |
| Zodiac | Joey Kuras |
| Jimmy "The Hammer" Valentine | Carl Edge |
| WMEW radio host | Matthias Bossi |
Edmund McMillen, the game's co-creator, voices Guppy himself. The rest of the credited cast keeps things in the family and the studio: Danielle McMillen on Lucy, Joey Kuras on Zodiac, Carl Edge on Jimmy "The Hammer" Valentine, and Matthias Bossi as the host you hear on the WMEW radio station. Five voices, five characters, no overlap. Everything past this table works differently.
How the cameo voices actually work
Here is the part that trips people up. The cats you breed are not individually cast. Mewgenics holds a pool of vocal sets recorded by its contributors, and each cat gets a random set pulled from that pool. The engine then pitches that set up or down to fit the cat.
The effect is that one contributor's recording can show up across an enormous number of cats, each sounding a little different because of the pitch shift. McMillen has described it as hearing the same cameo voice spread across millions of cats in countless variations. So when two of your cats sound oddly similar, they may be running the same underlying recording at different pitches.
Most of what these contributors recorded is cat noise, not dialogue. Meows, hisses, fight grunts, encounter chirps. They are there to make the cats sound alive, not to perform scripted lines. The five named roles above are the only true spoken-character voices in the game. Everyone else fed the meow machine.
This is why a standard "who voices this cat" question has no clean answer. There is no permanent link between a celebrity and a cat. You breed a cat, the game rolls a vocal set, and that set is whatever it happened to land on.
The cameo roster
Mewgenics credits close to 200 contributors to its cameo pool. The exact figure shifts depending on which credit list you read, but the roster runs deep into internet culture, comedy, music, and the games industry. You will not hear any of them as a named character. You will hear them as cats.
A few of the names worth knowing:
Streamers, YouTubers, and online creators
Markiplier, Jerma985, MoistCr1tikal, Vsauce, Vinny Vinesauce, Wendigoon, Northernlion, Hbomberguy, Corpse Husband, iDubbbz, Maxmoefoe, LilyPichu, Arin Hanson of Game Grumps, and Zach Hadel all contributed to the pool. If your feed has ever surfaced any of these creators, there is a decent chance one of your cats is meowing in their pitched-up voice.
Film, TV, and comedy
David Harbour, Felicia Day, and Bobcat Goldthwait lend vocals here, alongside Dax Flame, horror mainstay Barbara Crampton, Greg Sestero of The Room, and Rich Evans and Mike Stoklasa of RedLetterMedia. The cult-film and online-comedy crossover is heavy, which fits McMillen's audience exactly.
Musicians
Rivers Cuomo of Weezer, Logic, Tom Cardy, and Tay Zonday all recorded for the cameo pool. None of them sings. They meow.
Games and comics
Cliff Bleszinski turns up, as does Jhonen Vasquez, the creator of Invader Zim. McMillen's roots in indie games and underground comics show in who answered the call.
Treat every one of these names the same way: they contributed cat vocals to the shared pool. Saying any of them "plays" a particular cat would be wrong. The whole point is that they do not.
Why McMillen built it this way
The random-assignment design solves a real problem. A breeding game can generate a near-endless supply of cats, and casting each one would be impossible. By recording a pool and letting the engine shuffle and pitch it, the game gives thousands of distinct-sounding cats from a finite set of sessions. It also turns the credits into a game of their own. You never know which voice you are about to hear, and you cannot farm a specific one.
It rewards the core loop directly. The more you breed, the more of the cast you hear, because every new litter is another roll against that pool. Our breeding guide walks through how cats inherit stats, abilities, and mutations from their parents, and the vocal sets ride along the same generation-by-generation churn. For the detail on how traits pass down, the stat inheritance guide and the ability inheritance guide cover the math. Keep breeding and you keep meeting the cast.
The short version
Five characters in Mewgenics have a fixed voice: Guppy, Lucy, Zodiac, Jimmy "The Hammer" Valentine, and the WMEW radio host. Every other voice in the game is a cameo recording, mostly cat sounds, pulled at random from a pool of close to 200 contributors and pitched to fit whatever cat drew it. The celebrities are real and the names are wild, but none of them is bound to a single cat. That is the joke, and it is a good one.