Matarajin-sama 『(摩多羅神』is a shinbutsu (Shinto-Buddhist) syncretic deity of dubious origins. Similarly to Bishamonten, he's both a wrathful deva and a protector deity of a Buddhist concept, as well as various groups of people, such as burakumin, wanderers and actors.
Within esoteric practices, he's also considered a powerful kamisama of fate, and related to that, he is also associated with stars. More accurately, the Big Dipper, the Pole Star, and in some interpretations, Ursa Minor as well. In Zhiyi's, a Tiantai Buddhist monk's writings, he's considered a deity of Buddhist mediation through dream.
He's a source of hindrances, obstacles and ailments as well as a destroyer of them. These can be personal shortcomings, being prevented from reincarnating in the Pure Land, as well as illnesses and death.
While he's known to have been associated with Mahakala and the three-headed form of Daikokuten and thus has been depicted as an intimidating, monstrous figure, his most well-known image shows him as a smiling old man dressed in kariginu and Chinese officials' headwear along with two attendants, Nishita and Teireita. Despite that, he's seen as no less ominous; in fact he's considered to be a wrathful aspect of Amida Buddha.
Drums (specifically kotsuzumi) and okina noh masks are his primary symbols, but he's also associated with oxen through the Ushi-Matsuri.