Touda(called Guren by Masahiro) is one of the 12 shikigami that help Abe no Seimei. His fire burns everything to ashes which makes him feared. He always protects Masahiro because he was the first child to not cry when he saw him.
[Edit]Guren is one of twelve shikigami 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 shikigami still address him by original name. Only Seimei and Masahiro call him Guren.
The form he takes most of the time is 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. In episode 18 of the anime, it was shown that Guren tries very hard to avoid children, goings as far as to avoid entering dwellings with children even when his help is needed. According to Guren, the reason behind this is that children cry for no reason. Masahiro later notes that Guren's apprehension does not stem from the crying itself, but that Guren does not want the children to "cry at him" demonstrating that he is feared by loathed by everyone.
Masahiro later tries to comfort him by showing him that children are not afraid of him.