Paragraphs: You need them. Group subjects into paragraphs. Get a rhythm to how you write. I try to go 'Opening One liner' Paragraphs. Occasional one liner when I want to emphasize something.
The God's Prophecy: Is this the prophecy? How? I'm very confused.
Tense/Narration: First person? third person? Past/present? Is this a diary? Is Cheon Haneul talking to us?
Your First Line. This is the most important thing. WHAT GRABS ME AND MAKES ME READ THE REST OF THE CHAPTER. "A legend about the God's Apostle Descending upon the world." What is this? How about:
The God's prophecy was a legend about the apostle descending upon the world to...
WHAT? What is the apostle doing? The next line? Is the prophecy making the heavenly church or is the apostle making the heavenly church? Okay, you kinda clear that up by the third line but if you don't grab me in that first line, you lost half your potential viewers.
Why do I care? What is my investment? What do you have to make me want to know where the fuck this is going?
I might start with:
An elegant young man with a pale face and clean, black hair lay on a huge bed engraved with gold.
And ditch the prophecy until later.
That guy. I care about that guy more than I care about "Cheon Haneul, Am the 2nd in-line To the position of Cardinal In this Glorious Church." Maybe they are the same guy, but the guy on the gold bed is more interesting to me than the dry, impersonal cardinal. Start with the interesting guy.
Your exposition is a little too on the nose. Be careful when having people talk to themselves. Better to use Thought bubbles. I go with ~What he's thinking~. You can use italics, but I don't like doing that because I use italics in other parts of the book that aren't thoughts and I like to keep it separated. But whatever works for you.
Try using something more along the lines of:
X is doing Y, "SPEECH"
Image you are a camera. You are watching things unfold. Give me at least a bare minimum of what is happening. Is the speaker smiling when he speaks? Is he frowning? Is he twitching? Is he standing up, sitting down, walking to a window and looking out, examining a glass of water and wondering where he put his pills? SHOW, DON'T TELL. Even a few brief words will help to break up the pacing of the speech and let the audience breathe. Pacing is key. I read your first chapter and I feel like I have been hit with a wall of text. I don't know when I should pause to think about what I just read.
I suggest that you write everything out with Proper nouns, then go back and remove the proper nouns and replace with pronouns where it will make sense. For example:
Bob got out of bed. Bob looked around Bob's room. Bob walked over to the pull rope and summoned the butler. The butler arrived, "You rang, Sir Bob?" Bob nodded, "Bring me my tea." Bob sat down to wait.
To which I would then change to:
Bob got out of bed. He looked around his room. He walked over to the pull rope and summoned the butler. He arrived, "You rang, Sir Bob?" Bob nodded, "Bring me my tea." He sat down to wait.
A pronoun refers to the previous Proper noun until you add a new proper noun as the subject.
Suggestion:
Get TextEdit. It has a Text to speech function under 'Edit > Speech > Start Speaking' Listen to your story spoken out loud. This will point out to you all those things you aren't getting when you read your story. What you listen to and what you read are two different things and TextEdit will FORCE YOU to hear EXACTLY how your story was written. It will be painful, but it will be helpful.