Sesshomaru ("The Killing Perfection") is a great and powerful Inu Daiyokai (Celestial Dog), feared throughout the Feudal Era. He is the older half-brother of the hanyou Inuyasha and the first son of the Great Dog General, Toga. Unlike many other yokai, he had no interest in possessing even a single fragment of the Shikon no Tama to enhance his power, and even considered youkai who sought its abilities to strengthen themselves as pathetic and weak. Constantly wishing to improve himself, Sesshomaru regularly seeks out powerful foes to battle in order to test himself and improve on his skills.

Sesshomaru, born of a great demon bloodline, possessed the perfect power that many demons desired. Because of this, the Inu Daiyokai is almost always composed and confident in his power, displaying a calm, calculating personality at almost all times. Perhaps the only personality trait he inherited from his father was a fondness towards humans, which didn't manifest until much later on in his life. His calmness often kept his thoughts clear of emotional influence, making him extremely methodical and efficient in combat.

Having eventually accepted his younger brother as the rightful heir to Tessaiga, Sesshomaru eventually surpassed his father, and truly matured as an Inu Daiyokai. Manifesting in his regrown left arm was his new sword, Bakusaiga. With it, Sesshomaru became the strongest Demon Japan had ever seen.