A supernatural creature that brings harm or misfortune; used in folklore, fantasy, and metaphorically for dangerous things.
その森には魔物が住んでいると言われている。
It is said that a demon lives in that forest.
A demon appeared from deep within the forest.
彼は酒の魔物に取り憑かれたように飲み続けた。
He kept drinking as if possessed by the demon of alcohol.
勇者は村を襲う魔物を退治した。
The hero defeated the demon that was attacking the village.
He suddenly went berserk as if possessed by a demon.
This eerie incident is surely the work of a demon.
悪魔 specifically means a devil or Satan-like figure rooted in Western/Christian imagery, whereas 魔物 is a broader term for any evil spirit or demonic creature.
妖怪 refers to traditional Japanese folklore spirits and apparitions that are often mischievous rather than evil, while 魔物 stresses a harmful or malevolent supernatural nature.
魔物 is a broader native term for any monstrous or evil supernatural creature, whereas デーモン specifically evokes a demon figure from Western mythology or fantasy fiction.
魔物 covers any monstrous or supernatural creature with evil power, while 悪霊 is narrower, referring only to a malevolent disembodied spirit.
化け物 often refers to a shape-shifting apparition or freakish creature, sometimes used loosely for anything monstrous, while 魔物 more specifically denotes an evil, supernatural being that causes harm.
Laplace's demon
Compound of 魔 (ma, 'demon, evil spirit') and 物 (mono, 'thing, creature'). The exact historical derivation is uncertain, but the kanji combination has been used since at least the Heian period to refer to supernatural beings that cause harm.