Sumi and Gin's classmate and fellow hero. She uses a large spear in her hero form that can also be used as a shield. She's kind and thoughtful, but appears to have her head in the clouds often. In reality, despite her laziness and lightheartedness, she is very smart and has natural talent as both a hero and a leader, surpassing Sumi.
As a result of using Mankai too many times (20) to stop a huge Vertex invasion, she lost the use of most of her limbs and became unable to move, and afterwards was put in direct supervision of Taisha as a trump card. At the same time, due to sacrificing so much of her body to the Shinju, she became extremely respected within the Taisha and was considered as a near-deity.
She later appears in the anime series, where she informs Yuuna Yuuki and Mimori Tougou about the truth behind the Hero System and the world they live in.
In the end, due to the actions of the Sanshou Middle School Club, the Shinju gives back their bodily functions to the heroes, including Sonoko.
