Brittany Karbowski, English voice actress for Rimuru Tempest, has revealed the secret behind the slime's nasal voice. In an interview, she explained that she imagined the surface tension of water just before it breaks to create a tone that bounces inside a gelatinous body. An approach that blends basic physics with vocal performance.
Surface tension and voice modeling in animation 🎤
Karbowski applied a physical concept: the surface of a liquid behaves like an elastic membrane. For Rimuru, she aimed for the sound to be trapped within that membrane, generating a nasal resonance. Technically, this involved modifying the position of the tongue and soft palate, creating an artificial echo chamber. The result is a voice that sounds contained, as if vibrating inside a gel, without losing clarity in the dialogue.
The slime that talks like it has a cold 🤧
Who would have thought that to sound like a blue creature with isekai consciousness, you'd have to think about swimming pools. Karbowski basically turned Rimuru into a walking cold with superpowers. The irony is that the most powerful slime in anime owes its voice to a trick any child imitates when they pinch their nose. Science fiction, sometimes, just needs a pool and a bit of imaginary mucus.