Yomogi Asanaka (麻中 蓬 Asanaka Yomogi) is one of the main characters of SSSS.DYNAZENON. A high school freshman who works part-time at Inamoto's shop, his life changes when he gets caught in the conflict with the Kaiju and becomes one of Dynazenon's pilots.
On the way to school, Yomogi and his friends see Yume Minami sitting atop a floodgate, and discussed various rumors they heard about her, particularly about how she breaks her promises. While on his way to work after school, he found Gauma collapsed underneath a bridge. He remarks that he is hungry and that something had happened to him, and Yomogi gave him his Special Dog, saving him from starvation. Gauma tried to talk to Yomogi more and grabbed his ankle, but he runs away to his part-time job. The next day, Gauma chased after Yomogi while he was on the way to school, wishing to repay him for his kindness, but his appearance and demeanor instead scared Yomogi away. Coincidentally, he ran up to Yume and after a brief conversation, they agreed to meet up later. However, Yume never showed up.
Gauma later appeared to Yomogi again and seeing that Yume was already forty minutes late, Gauma decided to go and find her. When he did, he confronted Yume about her broken promise with Yomogi, talking so loud that Yomogi could hear him. Before the conversation could end, Shalbandes appeared in the city. Gauma attempted to "capture" it using his Kaiju user powers but found that he was unable to. The object in Gauma's bag started to shine, and upon taking it out it summoned Dynazenon, who took in Gauma, Yomogi, Yume and Koyomi Yamanaka as its pilots. Gauma controlled the entire mecha by himself, despite it being his first time in it. After a tough battle, Dynazenon changed into Dynarex and finished off Shalbandes.
In the aftermath, Gauma passed Dynasoldier to Yomogi and told the him and the others to meet again the next day to begin their training, but Yomogi skipped out to go to work instead, even when Gauma went to his house to confront him about it. After reluctantly going off with Yume, the two of them got to know each other better and Yomogi learned about Yume's dead sister. Despite Yomogi's lack of training, the four pilots defeat Greyjhom when it appears. The Kaiju Eugenicists made their presence known to the Dynazenon pilots and called out Gauma as a traitor, putting a sense of distrust into the others. When the Kaiju Burnaddon appeared, they were unable to unite their hearts because of their distrust towards Gauma, but were able to do so once again after he told them the real reason he pilots Dynazenon - so that he can meet with the person who entrusted it to him.
- While their characters have no relationship with each other, the voice actors for Yomogi and Chise, Junya Enoki and Chika Anzai respectively, are cousins in real life.
- Yomogi's parents divorced when he was in third grade, causing him to have to change his surname.