WARNING: There are major spoilers for anyone who has not read the novel.
I'll start with their first meeting.
When Oskar first meets Eli on October 22, she interrupts a revenge fantasy that he is playing out against a tree. She stands behind him on the jungle gym, and his first vision of her is indirect--a blurry reflection on the blade of his knife. This seems very symbolic, and could be intended to foreshadow Oskar’s future knowledge that Eli is a creature of violence, and the role that violence will play in drawing the two of them together. The image is blurred because, although he sees Eli, Oskar does not truly understand what Eli is.
In the First Letter of St. Paul to the Corinthians, probably the most well-known passage of the New Testament that talks about love, Paul writes, "At present we see indistinctly, as in a mirror, but then face to face. At present I know partially; then I shall know fully, as I am fully known." In our fallen state, we cannot see and know God perfectly, and therefore our love of God will be imperfect. Likewise, too, in our relationships with one another, we cannot truly love someone until we know that person, really understand who they are and choose to love that person. So although at this point Oskar really does not know Eli, perhaps his blurred image of her points to later developments in the novel, when he will begin to understand who Eli is, yet still come to love Eli.
One would think that most boys, being caught in such a situation, would immediately hide the knife, but Oskar actually turns and steps toward Eli with his knife drawn. Why is not clear; perhaps he is still caught up in the emotions of his fantasy, or perhaps it is the result of some subconscious reaction to Eli’s presence. He experiences a strange moment in which he fears that he might stab Eli, realizes what he is doing, and then puts away his knife. Then it dawns on him that Eli was not frightened by what he did. Eli, of course, has no reason to be frightened, but Oskar does not know this.
Their initial exchange is stand-offish. Eli does not immediately answer Oskar when he says ‘hi,’ and Oskar recognizes right away how strange she appears, with her doll-like appearance, and because she is outside in the cold wearing only a thin sweater.
Because Oskar lies to Eli about what he is doing, Håkan’s act of murder becomes the first topic of conversation. Earlier, Oskar sees a photo of the murder victim in the newspaper, and thinks he looks like the bullies who are tormenting him at school. “He looked like a Jonny or Micke. Maybe there was now an Oskar in the Vallingby school who had been set free.” Oskar considers whether his violent “game” could have caused the murder. And, instead of being horrified at the thought, he thinks of it as a new power that he must learn to control.
From all of this it can be seen that Oskar and Eli are unknowingly linked by violence from the first moment that they encounter one another. Without knowing it, Oskar is talking to the beneficiary of the murder, and Eli does not understand that Oskar has interpreted her victim as being one of the bullies, and entertained thoughts that he might have somehow caused the murder.
There is an interesting description of Oskar’s body language after Eli tells him that she cannot be friends with him. He defensively folds his hands over his chest and thereby feels the knife inside his coat. Only after Eli turns his back on him does he muster the courage to say, "What makes you think I'd want to be friends with you? You must be pretty stupid." Eli does not let this pass, and when she returns to challenge his remark, Oskar wraps his arms tightly around himself, presses a hand against his knife, and stares down at the ground. Oskar does not like genuine confrontation, and draws comfort from the presence of his knife. His reaction fits perfectly with the passive/aggressive nature of his unfolding personality.
Oskar notices three other strange things about Eli before the end of their first meeting. She smells like an infected wound; she admits to not feeling cold because "I've forgotten how to"; and she is very agile and strong, being able to jump down from a height of more than two meters without harming herself, and slam open the apartment door with one hand. All is not as it seems!
