The thing about Lucas Cader is that he seems entirely uncomplicated. He is Cullen and Gabriel's best friend outside their family, and he's probably the most socially well-adjusted kid in their group. Check it out:
You see, Lucas had power. He walked down the hall and you noticed him. You noticed his six-two swimmer's build and his messy brown hair that always looked like it was ready for a photo shoot. You noticed how he smiled at the pretty girls but always managed to say something nice or sweet to the not-so-pretty ones. (1.12)
He is so likeable and normal that it seems kind of crazy that he'd be friends with a couple of lone wolves. He is also the kind of friend who willingly drops anything to help his friends out, and even sleeps on Cullen's floor every night after Gabriel goes missing. It's clear that the Witter boys have somehow landed a dream best friend. But is he totally without depth?
Lucas's backstory is that his brother died in a car accident, and this affects him in ways that he's unwilling to admit in public:
What he had were watery eyes in the bathroom and a look of boredom and confusion when he thought no one was looking. And just before he would go to sleep at night, he would close his eyes tighter than I've ever seen and whisper prayers after crossing his chest. (3.84)
This pain is the reason that he is so good to his friends; in them, he sees his chance to be a brother again. As far as biblical connections go, well, we know that he prays to some higher power. More than that, though, his name can be seen as a shout-out to the Gospel of Luke from the New Testament, which contains both stories about the angel Gabriel and Jesus rising for the dead. Not sure why this matters? Check out Gabriel Witter's and John Barling's analyses elsewhere in this section.