Koyomi Yamanaka (山中 暦 Yamanaka Koyomi) is one of the main characters of SSSS.DYNAZENON. He is a 33 year old NEET who gets caught in the conflict with Dynazenon and the Kaiju, becoming one of the mecha's four pilots, along with Gauma, Yomogi Asanaka and Yume Minami.
Some time in middle school, Koyomi met Inamoto.
In his adulthood Koyomi became a shut-in NEET with a sedentary lifestyle, Koyomi seemed to have little interest in the world around him. This started to change when his cousin, Chise Asukagawa, dragged him along to go see the strange phenomenon in which entire buildings started floating in the sky. Soon afterwards, the Kaiju Shalbandes appeared in the city. When Dynazenon appeared, Koyomi was forcibly taken by the mecha and subsequently became one of its four pilots, shocking the cousin duo.
After defeating Shalbandes, Gauma passed Dynastriker to Koyomi and told him and the others to meet again the next day to begin their training. Koyomi goes under the pretense that he is being "employed" and that he might earn some money. 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.The