Тода

Guren is one of twelve Shinshō in service to Seimei, who gave him his current name, after he pledged his servitude. His original name is Tōda, (騰蛇). However, the other Shinshō still address him by his original name. Only Seimei and Masahiro call him Guren. The form he takes most of the time is an ayakashi although Masahiro considers him a mononoke, whom Masahiro named Mokkun. Because he's invisible to anyone without a spirit sense, Mokkun frequently plays tricks on people who annoy him, much to Masahiro's chagrin. It was also shown in the anime that Guren dislikes babies, because according to him, babies often cry for no reason.

However, Masahiro disagrees, saying that Guren was merely afraid that the children who saw him would hate him. From the time Masahiro was a baby, Guren watched over and protected him, as Masahiro was the only person who wasn't afraid of him. Because of this, despite how they constantly bicker with each other, Masahiro and Guren share a deep sense of friendship and trust between them and both are willing to lay down their own lives for the other. It is also mentioned that Guren is one of most feared summon gods, possessing the power of controlling the fires of Hell. Seimei also created a golden ring to wear around Guren's head to keep his own strength from overwhelming him.

Since Masahiro doesn't fear Guren, Seimei cites this as the proof his grandson is the only one compatible to be his successor. In the form of Mokkun, the familiar is able to erect barriers and project crescent shaped blades of energy; in the form of Guren, he attacks with blasts of fire and a trident. In the past, Seimei’s best friend Ryūsai who ordered Guren by using the Baku-kon spell, a spell that could forcefully control anyone’s heart. He used it on Guren to kill Seimei and after that kill him. In addition, because of that incident the other Shinshō don't trust him. Nevertheless, that began to change with Masahiro's help, as stated by Kōchin.