Say what??!...How do vampires relate to Christianity??...welll, they don't, actually (so please don't go watching it, if you haven't already, and think it is a Godly movie, cause it's not haha). I'm just using a point in the story and changing the perspective on it to share how something in the story can be made into a Godly perspective.
I think the relationship between the characters of Bella and Edward do, or at least it can be turned into a God-related topic...and here's why...
In the story, Bella's affection towards Edward is beyond a "normal" affection that typical relationships have, even in marriages. Bella is in constant 'need' of Edward, and she always wants to be with him. In fact, she would change her whole lifestyle in order to be "one" with Edward. A prime example of this is shown in the first book/movie called, "Twilight". When Bella and Edward have their first conversation in the science class/lab, Bella told Edward that she hated living in Forks, Washington because of all the cold and rain. But, after falling in love with a cold-blooded vampire, she started to love the coldness too, due to Edward himself being so cold at touch, and because the Cullen clan (Edward's family) liked to live in the colder climates. So, she was willing to give up her warm, sunny side to be with Edward's cold, rainy side. And, of course the whole idea behind Bella wanting to trade her mortal, human life to the immortal life of a vampire so that she could live with Edward forever is another prime example.
Looking at Edward's side of the story, he also desired to be with Bella all the time. His love for her was proven by protecting her, wanting the best for her, and loving her for who she was and wasn't. Examples of his love for her is shown throughout the series. He was always protecting her from other vampires who wanted human blood (eww). He tried to get Bella to change her mind about turning over to the "cold ones" (as Jacob Black referred to the vampires) side because he wanted her to live her life to the fullest and wanted the best for her.
Bella's relation to Edward is the same relationship people, especially Christians should have towards God. Our NEED for God should be so deep that we would trade our dreams and life to what God desires in us. Loving God should far exceed our love for anything or anyone else in our lives....including our spouses. I say this relates because Bella's love for Edward far exceeded her love for anything or anyone else in the story.
Desiring and longing to be with God should also be our focus, just like Bella longed to be with Edward. Living lives that pleases the One who made us, died for us, and rose again to prepare a place for us should be our hobby and determination while still on this Earth, just like Edward was Bella's determination.
Edward's relationship to Bella is how God relates to His people, I think. God wants to have relationship with everyone, in the same way Edward wanted and desired a relationship with Bella in the story. After all, God created each and every one of us, and with a purpose in mind. That purpose is to have a personal relationship with Him, and for us to share with others our testimony so to bring others to Him, as well.
So although the myths of vampires and the vampire story behind the Twilight series is not God-related, at all...if you dig deeper into the relationships the characters have, in particularly Bella and Edward's, you can pull out a deeper meaning behind them.
Our love towards God should be our number one focus. And, more importantly, God's love towards us is unconditional and unlimited. Praise God, right?!!