You say you are a religious person but you believe that demonic possession is fake even though the holy bible has many accounts of people being possessed? Gee, thats sounds a bit contradictory - how can you call yourself a believer without understanding that angels and demons exist and are quite capable of maintaining a physical vessel?
1. I'm not Christian
2. I'm Jewish, we don't believe in demonic possessions but we do believe in forms of spirits such as 'Dybbuks' which can cause weird occurrences but they can't posses a human. In Judaism we believe that if a demon was to posses a person, then it is basically saying that a demon has the same power as G-d. Therefore, demonic possession is not real
3. The "holy bible" is entirely based on our Torah (this isn't to offend anyone by the way)
4. Actually angels do exist, we place something called a 'mezuzah' on our walls which contains a script of the shema which is said to have angels guard our house from evil
5. 'Dybbuks' or evil spirits can appear if you go to a medium or play with an Oujia but stay away from Oujias and if you want a message from a spirit a medium will approach you with one