The heart of 'Let Me In' lies with Oskar and Eli. Their dynamic is the entire point of the book. Oskar is this incredibly lonely, bullied twelve-year-old who collects newspaper clippings about murders as a weird coping mechanism. Then Eli moves in next door, this strange, otherworldly kid who only comes out at night and smells faintly of decay. Their bond isn't sweet or innocent in a conventional way; it's built on shared loneliness and a terrifying understanding.
What's fascinating is Håkan, Eli's 'guardian'. Calling him a father figure is a gross understatement. He's a profoundly broken man compelled to procure blood for Eli through methods that are absolutely horrific. His sections are some of the most disturbing in the book, presenting a tragic, monstrous contrast to the purer need between the children. Then there's Virginia, a local woman who gets attacked. Her slow, agonizing transformation into... something else... is medical horror at its most visceral and pitiable. Through her, we see the full, grotesque cost of Eli's existence.
Lacke and the other neighborhood drunks are a Greek chorus of sorts, stumbling closer to the truth, providing this grimy, grounded backdrop against which the supernatural events feel even more stark. You root for Oskar, feel a twisted pity for Eli, and are horrified by everyone caught in the middle. John Ajvide Lindqvist doesn't write heroes and villains; he writes desperately sad people and monsters who used to be people.
It’s a novel about predators and prey in every conceivable sense, and every character, from the main duo to the bit players, is trapped in that cycle.