Suzu Mukai (向井 鈴, Mukai Suzu) is a blind girl who acts as a “stopper” for the intense cast surrounding her. Though her shyness and fear makes her speak in a slow stuttering manner, Suzu is noted by everyone as willing to speak what her heart tells her and is the first one in the class who calls for Horizon's rescue from her execution. Utilizing bell-like instruments on her belt and ears, she is also highly perceptive and is able to detect phenomena that escape most people’s attention, such as sounds from far away, as well as even differentiating near-identical ships through sound alone.
During the Spanish Armada, her sensing abilities are utilized by using her as an interpreter of external data delivered by the ship as sound, turning into a radar of sorts that can perfectly perceive Musashi's surroundings in a 30-kilometre radius.
Suzu has written on her essay that she likes Toori, and later follows up with the fact that she also likes Toori with Horizon as well as her other friends implying a similar stand in her romantic interest as with Nate Mitotsudaira.
- Sensory Device: Suspended-Type Hearing Aid "Otonari-san" (吊柵型補聴器「音鳴りさん」, Chousaku-kei Hochouki "Otonari-san") - Suzu's hearing aid, composed of a headphone that fully covers her ears and a set of tubular bells located in her clothing. This allows her to perceive auditory information from a circular area of a 30-kilometer radius with little distortion.