L is one of those rare characters who has a tragic past, and doesn't fucking bring it up as a sob story. He's an orphan for one thing, spent a good portion of his life, possibly from quite a young age, investigating gruesome crimes. He works so hard he barely even sleeps, completely disregards what everyone thinks of him and follows through with things to the very end when he knows he's right.
When he died, no one on the investigation team really cared. They were shocked, but they weren't saddened. They weren't sympathetic. He had no parents to cry for him and no friends to miss him. He was drawn with dead eyes for a reason.
But he never complained.