Kai Zimmer

Kai (カイ) is a recruit of the Survey Corps. He appears in the light novel Attack on Titan: Before the Fall 3 and the manga series Attack on TItan: Before the Fall.

Appearance
Kai is a young man with black hair, with the hair on the back of his head trimmed down much shorter. He wears a white shirt underneath the traditional uniform of the Training Corps.

Personality
Ambitious and brave, Kai shows a desire to join the Survey Corps with his squadmates. He exhibits bravery and wishes to fight against Titans for the sake of humanity, just like his hero Jorge Pikale.

Restoration of the Survey Corps arc
During a training session, Kai and his other squadmates come across an unconscious teen who washed up along the banks of a river. They take him to a nearby cottage for him to heal; due to being trainees at the nearby academy, they are only able to visit at night and do their best to help the teen recover. Roughly a week after they find him, Kai is informed by his squadmate Rosa that the teen is awake; him and his friends decide to return that night and learn the teen is named Kuklo. When Rosa says Kuklo is part of a mystery group that is developing a weapon to defeat Titans, Kai seems interested and expresses his overall desire to join the Survey Corps like Jorge Pikale; when he hears from Felix that Jorge will be there in a few weeks, Kai becomes excited at the thought of finally meeting his idol. Kuklo, after seeing Kai and the others' determination, offers to put in a word for them but cautions they will need to be serious about training. Kai becomes slightly unnerved when hearing Kuklo discuss several expeditions he took part of that resulted in the deaths of countless Survey Corps soldiers; nonetheless, Kai, along with the other recruits, promise to do their best.