Mimi "Mimi-chan" Tōmatsu is the head accountant in the Harekaze's supply team, handling all administrative duties, financial oversight, inventory management, and resource allocation. This includes meticulous record-keeping for purchases, supplies, and operational schedules such as bath rotations. Originating from Tokyo's Kabutochō Financial Fleet, her finance-focused upbringing motivated her specialization in accounting, logistics, and trading. She possesses strong academic skills in mathematics, holding Level 1 abacus and bookkeeping certifications, plus a third-class refrigeration machine operator license. Mimi habitually quantifies information using percentages, numbers, and comparisons, demonstrating a detail-oriented and methodical approach. As a hobby, she monitors stock and exchange trends but refrains from actual transactions. Mimi maintains an extensive, meticulously organized collection of photographs featuring Machiko Noma, whom she intensely admires; each photo is documented with its exact capture date. This admiration began during their shared entrance examination and manifests protectively. She exhibits visible distress when others interact closely with Machiko, notably becoming jealous when Akeno Misaki clung to her during a thunderstorm. Primarily focused on logistical support, she occasionally assists other departments like gunnery or navigation when needed. While generally reserved, her demeanor shifts in high-stakes situations, exemplified by courageous intervention during an altercation on the Ship Spee. This act earned her formal recognition for bravery and an award from Captain Thea Kreutzer. Her personal preferences include a fondness for sandwiches and chocolate bars, a favorite color of red, and an aversion to crab. She frequently uses the phrase "Quick thinking is worth a thousand gold coins!" and employs nicknames like "Mikirisenryou."