My Good Squire Noj, you ask honest and noble questions of which I shall try my best to answer.
Let is begin with your first question.
Where in the bible does it talk of the return of the nephilim?
This is why I ask people to read Matthew 24. In verses 37-39, Jesus says, "As it was in the days of Noah, so it will be at the coming of the Son of Man. For in the days before the flood, people were eating and drinking, marrying and giving in marriage, up to the day Noah entered the ark; and they knew nothing about what would happen until the flood came and took them all away. That is how it will be at the coming of the Son of Man."
We see from this passage that what will be happening on the earth at the return of Christ is the same things that were happening in the days of Noah at the time of the flood. Remember again what it says in Genesis 6:1-4, "When men began to increase in number on the earth and daughters were born to them, the sons of God saw the daughters of men were beautiful, and they married any of them they chose. Then the Lord said, "My spirit will not contend with man forever, for he is mortal, his days will be a hundred and twenty years. The Nephilim were on the earth in those days, and also
afterward , when the sons of God went to the daughters of men and had children by them. They were heroes of old, men of renown."
So again you see that it clearly states that
after the flood the Nephilim were still on the earth. This passage indicates that some angels sired children with human women. In doing so these angels sinned and became fallen angels. These offspring were hybrids called Nephilim, who were very large giants, probably over 30 feet tall.
As for the Nephilim hybrids, whose fathers were immortal angels, and whose mothers were mortal human women: when the Nephilim died their spirits were still immortal and active, but their bodies were dead like a pure human's would be. They became disembodied spirits. Like their fathers, they were bent towards evil in life, and also in death. These are "evil spirits" or "demons". The fallen angels who were their fathers were (before they became fallen) a type of angel originally known as a "watcher", or perhaps "guardian angels". This is a topic all unto itself which we can also get into as it pertains to this subject as well.
I know that is much to swallow all at once. Regarding your comments about Jude, remember that Jude directly quoted from Enoch in Jude verses 14-15. It is a direct quote from 1 Enoch 1:9. I do not believe the book of Enoch to be "Inspired". However, that doesn't mean it is not reliable. It we took that standard on everything that was not quoted in the Bible, the works of people like the great historian Josephus would not have any merit to them. We must be intellectually honest in how we apply our standards of judgement to what it "Inspired" and what is not, but yet is still good for historical accuracy. We at least have the benefit of the doubt in my opinion from Enoch because he
was quoted by the inspired book of Jude.
That is a lot to chew on and I will leave it at that for now. I do greatly appreciate your intelligence Noj and your heart for God. The very act of people coming to this thread and reading it means that God is planting seeds of hope in their hearts.
Many blessing to you for your comments. They are well thought out and I would love to keep the dialogue going. We have not even scratched the surface yet my friend.
May God go with you.