He was born in the basement of the University of Hawaii, in the Physical Science building.
His great-grandmother, Ethel Rathoi had been a native hawaiian, while his great-grandfather was a Norwegian rat that had jumped ship on Oahu. Olaf Ratson, a twenty-five pound stevedore, changed his name to the more generic "Rat" in order to make it harder for the police to catch him.
Ethel had been a normal lab-rat until, one day, she had been injected with a drug; one to enhance her fertility. It was successful in that endeavor, and also gave her both a human level intelligence, and longevity.
With her increased intelligence, the cage locks were no real challenge. Ethel let all the laboratory creatures out. While they scattered to the winds, Ethel, smartly, headed downward and into the basement. She met Olaf there, where he was hiding from port authorities. The two soon had a litter of children, then another. By that time, the first litter also had children.
It didn't take long before the basement was flooded with intelligent, long-lived rodents.
Old Ethel was the head of a matriarchy. She insisted her progeny take classes upstairs. They would sit inside ratholes, taking notes as the instructors taught. The family also had access to all the textbooks and, at night, the library.
The children were also taught to keep the basement and all other areas clean, and not to make a mess in the human parts of the building. That way, Ethel figured, they would remain unnoticed by humans.
Although one of the most intelligent students in the fourth generation, Oscar varied from the norm. The young rodent had a spirit of adventure in him. Oscar read equal portions of Shakespeare and travelogues.
Taking off one day, to see the world, he was almost eaten by some cats. Now, Oscar was big enough and mean enough to handle most pussies, but even Oscar hesitated to take three of them on.
He was rescued by me. My name's Charlie, Oscar's best friend. I took him into my apartment, calmed him, and fed him a frozen pizza. We've been friends ever since that day.
After I moved back to Ohio, Oscar went on many adventures, all over the globe. He finally showed up on my doorstep, hearing I was a writer. Oscar wanted to try writing for a living.
He has many stories to tell, over three hundred right now, some even published on paper. He sees his mission as telling humans the true story of ratkind, the one not in human history books. His stories and novels all have rats as heroes, and are all based on true stories. Although a good guy, and a great friend, Oscar is still, at heart, a rat.