I am fascinated by ghosts.  Do you know what Yokai are? 
Yeah! Yokai are actually part of Japanese folklore. 
What do they do in Japanese folklore? 
They were mostly supernatural spirits used in Japanese folklore.
Were they evil spirits or good spirits? 
Every spirit was different. There were good spirits, called nigi-mitama and violent spirits, called ara-mitama. 
Were the two different spirits at war with each other?
mitama", brought ill fortune—including illness and natural disasters. One's ancestors and particularly-respected departed elders could be deemed "nigi-mitama", accruing status as protective gods and receiving worship. Animals, objects and natural features or phenomena were also venerated as "nigi-mitama" or propitiated as "ara-mitama"—depending on the area.
The ritual for converting "ara-mitama" into "nigi-mitama" was called the "chinkon" ("the calming of the spirits").
spirits beings are called yokai in its folklore.
Other Japanese religious leaders claiming to channel spirits include Ryuho Okawa of the Japanese new religious movement Kofuku-no-Kagaku, or Happy Science, who claims to channeled the spirits of Muhammad, Christ, Buddha, and Confucius.
Beliefs Pacific islands.
In Samoa, Java, Tonga etc. distinctions are made between god-like and spirit-like beings, with gods representing the moral order and spirits dealing with periphery issues, both through channelling, mediumship and possession.