Near is L.
Correction: Near is L, perfected.
Near is L, minus his humanity. Near is L, minus his inconsistencies. Near is L, minus his flaws. Near is L, with heightened reasoning ability, lowered sense of fair play, and infinitely squared obsession with winning. L may have been the great detective, but Near, Near was the great detective's greatest strengths, all his abilities, all his unstoppable might, but without those irritating little human additives. L hadn't loved in so long he'd just about forgotten how, but Near, Near never learned at all. Near is a machine, sees all, knows all, is all, and such a creature was never born to love.
And Near knows, he knows, thisis undeniable fact. He brought down Kira! Succeeded where L had failed! (With Mello's help, admittedly, but remember, Near, remember? Mello is dead.) He wasn't the original, he was better than the original, he was flawless, precise, a diamond in a world of rocks, untouched and brilliant.
Near knows, he knows, this is undeniable fact. He's perfect, flawless, unfettered by the ties of being human, and still he is inferior.
And Near will never know that, never understand that, and when he dies four years later of a heart attack still not knowing, oh, it irks him to no end.
I was cleaning out my files and found this. This is two or so years old and unedited, and thus pretty bad.
I don't remember what plotting I did to lead to Near's death, but I'm sure it was very elaborate and brilliant. Feel free to guess!