Nintendo claims Dark Souls 3 mod isn’t 'valid prior art' in Palworld's Pokémon patent case

The legal battle between Pocketpair’s Palworld and Nintendo is still ongoing. A debate has interestingly emerged over whether a 2020 mod for Dark Souls 3, known as Pocket Souls, could serve as prior art to invalidate Nintendo’s patents on Pokémon-style creature-capturing mechanics.

The mod brought into question during the Nintendo Palworld lawsuit was released on September 12, 2020, via Nexus Mods, which transformed Dark Souls 3 into a somewhat Pokémon-like game. Players could capture enemies in Dark Souls 3 in an Abyssal Flask and pit them against other enemies or bosses in battles.

Pocketpair used this mod along with games like Final Fantasy XIV, Monster Hunter, and its previous 2021 game Craftopia, as evidence that the core ideas behind Nintendo’s recent patents were already in public use long before the company filed them.

Nintendo and The Pokémon Company filed the lawsuit against Pocketpair in September 2024 in the Tokyo District Court, which centers around three Japanese patents related to collecting creatures and aiming systems. The original patent application was submitted in late 2021, just before the release of Pokémon Legends: Arceus, which encompassed the broader mechanics of capturing and displaying creatures in a Poke Ball-like fashion.

Palworld enjoyed an explosive launch in January 2024 and sold over 25 million copies in its first month. Following Palworld’s success, Nintendo registered divisional patents in 2024, which narrowed in on the Poke Ball’s mechanics, such as aiming indicators and capture success rates. 

These divisional patents finally became the backbone for Nintendo and The Pokémon Company’s infringement claims, with the company seeking an injunction to halt Palworld’s distribution and damages of approximately 10 million yen or $67,000.

In response, Pocketpair has put up a multi-faceted defense and argued non-infringement and invalidity via multiple prior art references, any one of which could nullify Nintendo’s patents. Among these, the Pocket Souls mod is a major example, predating Nintendo’s 2021 filings by over a year. 

However, during recent court pleadings, Nintendo pushed back aggressively and asserted that mods like Pocket Souls cannot qualify as prior art because they “can’t run without underlying games” and thus do not constitute independent inventions. 

Nintendo’s position has been outlined in two separate filings, which aim to exclude community-made mods from the pool of eligible references, in an attempt to limit what could be deemed admissible in court.

Patent analyst Florian Mueller has described Nintendo’s stance as an “extreme” one, mentioning that “courts usually reject attempts to narrow the pool for prior art references in unreasonable ways. We are concerned about what an adoption of Nintendo’s views by the Tokyo District Court and potentially other courts in the world would mean for the modder community.”

Mueller further wrote, “Apart from utter disregard for the enormous creativity with which modders contribute to game-related innovation, modders would become ‘fair game’ as their ideas could be patented by someone else (unless they file for patents first, which modders typically don’t) and then, depending on the specific prior use rules in a jurisdiction, be used against them.

For example, in the United States, the thief would just have to file patents within less than a year of the release of the given mod.”

The implications of Nintendo and Palworld’s ongoing heated lawsuit extend beyond Pocketpair’s blockbuster title, as Nintendo has had a history of cracking down on fan-mods, including takedowns of Pokémon-themed add-ons for Garry’s Mod and a multiplayer mod for The Legend of Zelda: Breath of the Wild, Another Metroid 2 Remake, Pokemon Uranium, Super Mario 64 HD, Full Screen Mario, and The Legend of Zelda: Ocarina of Time 2D.