Isshin Ashina, also known as the Tengu of Ashina, is a pivotal character in Sekiro: Shadows Die Twice. He is a legendary swordsman and the founder of the Ashina clan, known for his prowess in battle and tactical brilliance. Throughout the game, Isshin serves both as an ally and an antagonist, embodying the complex morality of the Sengoku era. His ultimate goal is to preserve the Ashina clan's power, leading to a conflicted relationship with the protagonist, Wolf. Isshin is a mentor figure, imparting valuable wisdom and combat skills to Wolf, while also challenging him in profound ways.