Sonoko After (Sonogo no Sonoko) is a bonus story featured in the Yuki Yuna is a Hero Visual Fanbook. It takes place directly after the first season of the anime and tells the story of Sonoko, once again moving around and making friends with her fellow club mates.
- Concept Designs: Takahiro (Minato Soft)
- Illustrator: BUNBUN
The story begins with Togo Mimori, Nogi Sonoko, and Yuki Yuna discussing the fallout of the last Vertex battle. Although they are sure the Vertex will attack again, they know that right now they can focus on recovering.
Several months later, as Yuna and Togo are walking to school, a black limousine stops in front of them. Sonoko steps out, revealing to the two of them that she will be attending Sanshu Middle School. She also joins the Hero Club, and creates nicknames for the other girls. The club celebrates Sonoko's initiation by going to the udon shop.
After the celebratory meal, Sonoko returns to her house with Togo, where they discuss the Taisha's future plans, such as updates to the Hero System and the full disclosure of what lies beyond the wall. Sonoko also mentions Yuna, suspecting something is not right with her.
The story ends with short scenes at the Inubouzaki house, where Inubouzaki Fu mentions to Inubouzaki Itsuki how she misses Inugami, and at the beachfront, where Miyoshi Karin trains with her swords until Yuna runs over to her.
- One of the plans that Sonoko hints at eventually becomes the "kuni-zukuri" ritual performed by the Sentinels in Kusunoki Mebuki is a Hero.
- This is the first use of the word "Messiah", someone who has the powers of both a hero and a miko.