This stems from the fact that the direction between Ushi (ox) and Tora (tiger), which is northeast (Ushitora), is called Kimon (ogre gate), and an oni was supposed to have the horns and body of an ox, have the fangs and claws of a tiger and wear a tiger skin.
これは、丑の方と寅の方の間の方角（艮うしとら）を鬼門と呼ぶことによるもので、牛の角と体、虎の牙と爪を持ち、虎の皮を身に付けているとされた。