Ghost in Chinese / Japanese...

魂魄 is a Chinese, Japanese Kanji, and old Korean Hanja term for ghost, soul, or spirit.

It's used in the context of Buddhism as:
Animus and anima; the spiritual nature or mind, and the animal soul; the two are defined as mind and body or mental and physical, the invisible soul inhabiting the visible body, the former being celestial, the latter terrestrial.

This Chinese, Japanese Kanji and old Korean Hanja word can be defined as devil, ghost, apparition, phantom, specter/spectre, demon, monster, or goblin.

妖魔 means demon in Chinese, and perhaps slanted towards ghost in Japanese.

幽靈戰士 means Ghost Warrior or Ghost Soldier in Chinese.

This title is used for at least one movie, and a video game (about a sniper).

鬼 can mean ghost, ogre, demon, or "spirit of a deceased person", in Chinese, Japanese Kanji, and old Korean Hanja.

In some context, it can also mean sly, crafty, ogre-like person (i.e. fierce, relentless, merciless, etc.)

This can also be the "ghost" constellation (one of the 28 mansions in Chinese folklore).

An extended list of meanings includes: departed; dead; a disembodied spirit; dead person; evil being; hungry ghost.

鬼武者 is an unusual title that can be translated two ways, daredevil warrior or demon warrior.

The most common is probably the daredevil warrior. However, the first character means demon, ghost, or soul of the departed. Therefore, it can kind of mean soul of a warrior, or a demon warrior.

This title is Japanese only, and should not be used if your audience is Chinese.