Driscoll Berci, a Quincy and Wandenreich Sternritter designated "O" for "The Overkill," cuts an imposing figure nearly twice the height of an average Shinigami. His black hair flows into a chinstrap beard, complementing his Sternritter uniform: a white hooded cloak over a thigh-length trench coat secured by a chain-adorned black belt, white cravat, white pants, and black shoes. He embodies bloodthirsty remorselessness, openly mocking opponents in battle while scorning weakness and rejecting mercy. This ruthlessness surfaces when he taunts Lieutenant Shūhei Hisagi about the humiliation of powerlessness. During the Wandenreich's first Soul Society invasion, Driscoll joins the Black Ridge Gate massacre of 106 Shinigami. There, he defeats 1st Division Lieutenant Chōjirō Sasakibe. Using a Quincy medallion, he steals Sasakibe’s Bankai, Kōkō Gonryō Rikyū, then impales him with a Heilig Pfeil—a colossal spiritual arrow that launches Sasakibe’s body to Captain-Commander Yamamoto’s office. In the subsequent Seireitei assault, Driscoll overpowers Hisagi while boasting of his Schrift, "The Overkill." This ability augments his strength with every life taken—enemy, ally, or beast—and he claims 200 Shinigami kills amplified his power. As he prepares to execute Hisagi, Yamamoto intervenes. Driscoll retaliates by unleashing the stolen Bankai’s lightning against Yamamoto, who withstands the strikes and annihilates Driscoll in a single slash of his Shikai, Ryūjin Jakka, reducing him to ash. Driscoll employs a Quincy medallion for Bankai theft and Reishi Tekkō—spirit-metal fistbands generating javelin-like Heilig Pfeil. These arrows pierce captain-level Shinigami and hurl victims vast distances. "The Overkill" grants temporary power surges per kill, though effects reset after eating, sleeping, or fainting. Despite wielding Sasakibe’s Bankai, Driscoll cannot harness its full strength due to inadequate training. Yamamoto observes the Bankai’s diminished output under Driscoll, a critical limitation compared to Sasakibe’s mastery.