The mernorns worked, to a degree. But some Shee decided that they didn't like how the mernorns ended up. So they wanted to invent a new breed of amphibious norns, ones that could go from land to water and back. This way the Shee could keep their norns during most of the year, and release them into the ocean during the winter.
They took their smartest norns, and began to improve them. They made them smarter, calmer, and more adaptable to extremes in temperature. They added feathers instead of fur, and a set of gills that could be used so they could stay underwater for a longer time. And so the penguin norns were born.
I created these norns to complement a COB I had found, an underwater city that went into the dark sea. I started with normal amphibious norns, like those on Frimlin's site, but they kept complaining about the cold. So I decided to make a new, improved version of them to live in the underwater city. That was the beginning of the penguin norn.