- Daughter of a male Malagasy giant rat (votsovotsa) and female black domestic mouse (Hypogeomys antimena × Mus mus domesticus).
- The name Nomena is Malagasy for "given".
- A mouse hybrid beautiful in appearance and wardrobe, Nomena was once part of a secret fellowship that claimed to hold the key to near-immortality: a potion that could only be used nine times (per feline tradition) throughout a single given lifespan, thus enabling Nomena to witness nearly all of Malagasy history. Her first rendezvous with Sam, then aged 8½, forms the basis for the tentative sixth and final book in the Unspooled series.
- Nomena "regenerates" every 60-90 years thanks to a magic potion; in her current ninth and final form (begun on August 8, 1981), she is the girlfriend of raccoon cousins Sam and Alfred.