I realized recently in a Question of the Day on https://rpggeek.com that although nearly every fantasy tabletop roleplaying game (tt-rpg) included animals as pets, resources, and assets, none of them really gave a treatment of the animals as an entity onto themselves. Instead of being treated as loyal sidekicks, they are always treated as an extension of a player character (PC) or an extra attack or just a conditional bonus.
Thus, I decided to create an algorithm I could use to give these favored assets personality. In order to do this, I delved into research about how our pets and domestic animals are different than their wild equivalents. As it turns out, this is an extremely busy and overwhelming area of research amongst biologists and geneticists alike. What follows is my attempt to use this research to create an rpg animal companion rules that make your rpg animals come alive. I hope you enjoy reading and using this supplement as much as I obsessed over writing it!