Hi Iridesa, I don't know what the dream means, but it does sound more than just a dream-and actually has a spiritual meaning.
In the Chronicle of Narnia- the Lion was originally intended to represent Jesus Christ— according to the author who originally wrote the series many decades ago- before it was made into a movie. In the Hebrew scriptures, Christ is also called the Lion of the Tribe of Judah as well- so there seems to be a parallel there.
Also– the fact that this Lion in your dream seems to have alot of authority and is warning everyone to get out of the castle- because it is shutting down and becoming dark- sounds very very much like God warning everyone in the World to come out of the World system –where we find so much luxury and comfort . Like this World system is going to go through a change where it will be completely taken over by forces of darkness– where there will be a Dark Ages occuring so that this Lion (who represents Christ) is warning all those who have Light within them to get out before it's too late. Do get out and go towards true Light — so we wont be in the permanent dark.
The black snake in your dream represents forces of Darkness– diabolic entities who are involved in this battle between dark and light going on in the heavenly realms right now.
The fact that you were the white snake may symbolize that you have God's Light within you- and ultimately, the Creator's Forces of Light will win over the forces of darkness. God is within people- His spirit is inside everyone who embraces Love and Light- and He is within you as well- so it wasnt you batteling the black snake, actually- but God inside of you.
That's just my 2 cents worth of interpretation! Like I said- your dream does sound very spiritual and I know you're not a Christian, but it very much seems that the Christian God was involved with this dream you had. Seems it is prophetic of times to come–
hugs!
Lisa Grey Eyes