In 1560, Japan's last Shogunate has lost its grip on the country, and the vacuum has filled with clan warfare. Among the factions competing for supremacy is the Steel Claw, led by Daimyo Mamoru Imai—a commander who has turned to forbidden practices and dark entities in search of an edge over his enemies. When a vindictive and ancient samurai warlord's spirit possesses Mamoru, the Steel Claw becomes something far worse than a regional power play: a force of pure corrupting darkness spreading across the land, allied with nine other powerful demons. No single army can stop it. The shinobi clan Black Lotus has been assigned the only viable counter: targeted assassination. Within the Blade is a stealth action game built around the Black Lotus's infiltration and elimination campaign against Mamoru's possessed forces.