From the introduction: Compatible Games: This ruleset can work with any main series Pokémon RPG game, but is most suited for Generation IV or later, after moves were given a damage category individually, rather than by type. User summary: Requires the use of d20-based Pokémon-capable RPG. The product uses artwork with a claim of fair use via an online wiki - it is not clear whether this infringes on copyrighted intellectual property.