Arknights is a tower defense mobile game developed by Chinese developers Studio Montagne and Hypergraph. It was released in China on 1 May 2019, and worldwide on 16 January 2020 by Yostar. Arknights is available on iOS and Android platforms and features gacha game mechanics. The game is set in the dystopian, post-apocalyptic future setting of the planet Terra, where people exhibit kemonomimi features – characteristics of animals or mythological races. Natural disasters leave behind a valuable mineral, Originium, which enables the use of "Arts" (magic) and often infects people with a progressive disease, Oripathy. Due to the disease's 100% mortality rate, and its high infectivity at the time of death, hostility towards the Infected became widespread, leading to their mass quarantine and expulsion by governments worldwide, and sparking tensions between the Infected and non-Infected. The player takes the role of the masked and amnesiac "Doctor", who commands a team of "operators" of Rhodes Island, a pharmaceutical, medical, and self-defense organization. As Oripathy spreads, the team must search for a cure while defending themselves against the Reunion Movement, an Infected anarchist military force bent on overthrowing the governments of Terra in revenge for persecuting Oripathy victims.