Sega files patent infringement lawsuit against Memento Mori developer over in-game mechanics, seeking 1 billion yen in damages 

Japanese mobile game developer Bank of Innovation (hereafter BOI) announced on October 21 that it has received notice of a patent infringement lawsuit lodged against it by Sega Corporation. This comes only a month after Nintendo and The Pokémon Company made headlines for suing Palworld over patents related to in-game mechanics. 

Sega claims that two titles developed and operated by BOI infringe on their intellectual property. This includes Genjuu Keiyaku Cryptract, a mobile RPG run by the company from 2012 until 2019, and the AFK RPG Memento Mori. Memento Mori was initially launched in 2022 and has since significantly grown in popularity, receiving a PC version and English release. The game has been so successful that it accounted for over 90% of BOI’s net sales at one point (source: Otaku Souken). 

Sega and BOI had been going through negotiations regarding the alleged infringement, but unsatisfied with BOI’s response, Sega ultimately decided to file the lawsuit. In the lawsuit, Sega is seeking an injunction for patent infringement and over 1 billion yen (about $6.6 million) in damages. BOI believes that there is no basis for infringement in their games and intends to verify the claims during litigation. The developer intends to continue running Memento Mori regardless of the outcome of the lawsuit. 

Sega alleges infringements of the following five patents: No. 5930111, No. 6402953, No. 6891987, No. 7297361 and No. 7411307, all of which are registered in Japan.  Given that the patents describe gacha-related mechanics such as synthesis and ceiling systems which are widely used in mobile games, the case is attracting a lot of attention.