The creator of popular Switch emulator Yuzu is the target of Nintendo’s latest anti-piracy lawsuit, with the gaming giant claiming in its suit that “there is no lawful way to use Yuzu to play Nintendo Switch games.”

The lawsuit, picked up by Game File’s Stephen Totilo, is seeking “equitable relief and damages” from Yuzu creator Tropic Haze, alleging that the emulator unlawfully circumvents its copyright protections, knowingly “facilitating piracy at a colossal scale.”

Nintendo adds that subscriptions to Yuzu’s Patreon doubled during the period the leaked game was available, claiming “on information and belief, thousands of additional paid members of Yuzu’s Patreon signed up so that they could download the early access build and play unlawful copies of Zelda: TotK.” Nintendo also notes that Yuzu banned discussion of emulating Tears of the Kingdom from its Discord during this period, claiming this as proof that the developers knew the software was being used for piracy.

The core of Nintendo’s lawsuit focuses on the fact that Yuzu requires decryption keys from the Nintendo Switch to decrypt and play games on its emulator, and while Yuzu doesn’t provide these itself, it provides links to software that can extract them from the console. Nintendo also quotes Discord messages from lead developer “Bunnei” acknowledging that most Yuzu users pirate these keys and the Switch games they want to play–though Nintendo also notes that ripping games and keys from your own Switch is still unlawful.