There are demon-like beings in Buddhism. Mostly they are in the realm of hungry spirits and the lower heavens. These are for example the naga (aquatic serpent demons), yaksha (nature spirits), rakshasa (man-eating demons), pishacha (flesh-eating demons), kimnara (centaurs), asura (warrior gods), mahoraga (subterranean serpent demons).
"If the Buddha-Nature is seen, there will be no seeing of a nature in any thing."
(Nirvana Sutra, T12n374p521b3; tr. Yamamoto)
"Neither cultivation nor seated meditation — this is the pure Chan of Tathagata."
(Mazu Daoyi, X1321p3b23; tr. Jinhua Jia)
"With sudden enlightenment to Tathagata Chan,
The six paramitas and myriad means are complete within that essence."
(Yongjia Xuanjue, T2014p395c14; tr. from "The Sword of Wisdom")