Shinpachi Nagakura captains the Shinsengumi's 2nd Unit, blending a carefree, humorous exterior with profound loyalty and strong principles. Initially distrustful, he advocates executing Chizuru Yukimura upon her discovery due to security concerns, demanding proof of her gender. He relents when her identity is confirmed, acknowledging harming a woman conflicts with his values. This pragmatic yet principled stance guides his duties, including participation in torture or lethal force deemed necessary for the group's objectives. He displays a boisterous, friendly demeanor, often bantering with comrades like Harada Sanosuke and teasing Toudou Heisuke. Known for frequenting Kyoto's Shimabara district for alcohol and female companionship, he nonetheless possesses keen situational awareness and political insight, surprising others with his articulate grasp of complex events. He consciously maintains a cheerful facade to boost morale during crises, even while wrestling with internal doubts. A highly regarded master swordsman, Nagakura incurs a severe hand injury defending Chizuru from attackers during the Ikedaya incident, prioritizing an ally's safety over his own. This self-sacrificing tendency intensifies, leading him to physically shield comrades. His fearless commitment is further demonstrated when he leads a suicide squad against Imperial forces during the Battle of Toba–Fushimi. His core ideals ultimately drive his departure from the Shinsengumi after the Battle of Kōshū-Katsunuma. Disagreeing with Kondō Isami's directive for survivors to become his personal retainers, Nagakura leaves alongside Harada Sanosuke to form the independent Seiheitai unit, prioritizing personal principles over group loyalty after years of service. His relationship with Chizuru evolves significantly. Initial hostility gives way to mutual respect, particularly after she tends to his Ikedaya wounds. His protective instincts toward her grow pronounced, reflecting his broader commitment to safeguarding those he deems worthy of trust.