1girl bangs black_hair black_sailor_collar black_serafuku black_shirt black_skirt blood blood_on_clothes blood_on_hands blood_on_weapon chromatic_aberration commentary from_behind full_body highres holding holding_sheath holding_sword holding_weapon katana kuro_kosyou long_hair long_sleeves looking_at_viewer looking_back original pleated_skirt profile red_eyes sailor_collar school_uniform serafuku sheath shirt skirt solo standing sword symbol-only_commentary unsheathed very_long_hair weapon white_background