The focal point of Mamoru's mission. Yuuna is sweet-natured, completely oblivious, and a magnet for disaster. Her character drives the plot forward, as her innocence often leads her directly into the hands of villains. While she can sometimes fall into the "damsel in distress" trope, her genuine kindness serves as the emotional anchor for Mamoru's grueling training. Mairu Sawamura

: Voiced by Mamiko Noto . A wealthy classmate who acts as Yūna’s best friend. She is cynical about childhood romances and often insults Mamoru (calling him "Ahoru"), but she secretly has feelings for him, leading to a classic Tsundere dynamic.

For example, a flower pot falls from a balcony. Yuna looks up, frozen. The audience sees a blur of motion—a hand reaching out, catching the pot, and vanishing in a split second. Yuna blinks, wondering how the pot shattered on the ground away from her. Mamoru is seen in the background, adjusting his glasses, looking perfectly normal.

While the plot is enjoyable, the characters are the true strength of Kage Kara Mamoru! The series expertly builds a "harem" of female leads who orbit around Mamoru, each with distinct personalities and motivations. However, unlike many modern shows, Mamoru is notably not a pervert; he is a genuinely nice guy who treats everyone with respect.

Watching Kage kara Mamoru! today is like flipping through a high school yearbook from 2006. The animation, handled by Group TAC, possesses that distinct mid-2000s gloss. The character designs are sharp

A refined, wealthy girl who commands a faction of modern-day ninjas. Airi initially acts as an antagonist, seeking to prove her clan's superiority over the Kageki family. After being soundly defeated and subsequently saved by Mamoru, she shifts into a fiercely loyal—and incredibly wealthy—suitor. Hotaru Kumogakure

A competitive, short-tempered shrine maiden (Miko) who wields a bladed boomerang. Mairu originally views Mamoru's nerd persona with disdain, but after witnessing his hidden ninja skills, she falls deeply in love with his alter-ego. Her constant attempts to get closer to him provide some of the show's best comedic friction. Airi Tsubaki