騰蛇 / 紅蓮 / もっくん, Guren, Mokkun
Guren is one of twelve Shinsh in service to Seimei who gave him his current name after he pledged his servitude. His original name is Tda . However the other Shinsh 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 hes invisible to anyone without a spirit sense Mokkun frequently plays tricks on people who annoy him much to Masahiros 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 wasnt 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 Gurens head to keep his own strength from overwhelming him. Since Masahiro doesnt 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 Seimeis best friend Rysai who ordered Guren by using the Bakukon spell a spell that could forcefully control anyones heart. He used it on Guren to kill Seimei and after that kill him. In addition because of that incident the other Shinsh dont trust him. Nevertheless that began to change with Masahiros help as stated by Kchin. Later in the series he is corrupted by Chishiki no Gji losing his soul and becoming a coldblooded monster who almost leaves Masahiro to die. It is later revealed that hes a slave of the Underworld as he controls the Fires of Hell. His blood was required to break the final seal of the gate to the Underworld. At the end of the anime Masahiro revives Guren saving his life in exchange for Gurens memories of Masahiro being sealed away so he would not have to remember and regret the terrible things he has done. Despite Guren having no memory of who he is Masahiro felt that this was better than seeing him die. However Guren is sill one of Seimeis familiars. As such he is under orders from Seimei to continue to look after Masahiro. Source: Wikipedia