Lost Soul Aside is a fast-paced third-person action slasher game set in a fantasy setting, inspired by Final Fantasy XV and Ninja Gaiden. The events of the game will tell the story of the former Templar Kaiser, who caught a war between two kingdoms and lost his family during the battles. Ten years after the end of the war, monsters began to threaten people. Kaiser managed to unite with one of the monsters named Arena and pursue common goals together.