. Yagami Light - brilliant, cold, deviously manipulative and calculating young man with a childishly myopic and exaggerated sense of justice. He has a gross disregard for the lives of others and often uses them as pawns in his schemes.
. L / Ryuuzaki: A quirky, disheveled, cake munching genius and sleuthing prodigy that uses his talents to solve difficult crimes and mysteries better than men three times his age. Can also be non-chalaunt in the well-being of others when his goals are concerned.
UBER SPOILERS AHEAD!
It's established fairly early in the anime that L/Ryuuzaki and Light are two very uncommon young men with very much in common. They're both childish, hate to lose and have very strong views on what they believe justice is. Of course they're both brilliant, stand out amongst their peers, and are great at tennis. They often compliment or acknowledge each other's intelligence. They're always watching each other's every move, trying to size the other up, or read the other's mind. Not surprisingly, even their inner monologues are the same. They practically think in tandem.
L is the only person that's able to get under Light's skin and crack his cool controlled exterior. Light is the only person who was able to force L to get physically and emotionally involved in a case. Light is only pissed off by L and vice versa, sometime even to the point of violence. As the plot progresses, L and Light, even though on opposite sides of the law end up spending a great deal of time together. There's even a point where L says Light is the only person he's ever thought of as a friend. After hearing that suddenly Light's plans to do away with L seem to constantly be delayed. Ryuk, Light's shinigami, laughingly points out that Light is so hesitant to have L killed because he said he thought of him as a friend. There's one instance where Light's "girlfriend" MIsa-Misa comes to see him while he's talking to L. Light actually walks between her and L so that she can't see L's real name and kill him.
Speaking of Misa-Misa, Light seems to have no love or respect for women. Bubbly women annoy him to no end
and even cool, intelligent women are little more than a trifle to him. As much as they may like him, Light has
absolutely no qualms about stringing them along to meet his goals. MIsa-Misa/Amane, his pretend girlfriend,
throws herself at him, loves him unconditionally, and shortens her life just so she can be of some help to him.
But Light uses every opportunity possible to be rid of her. Light uses, manipulates and abandons or kills every women he's comes in contact with.
L's constant suspicion of Light being KIRA prompts him to decide that one way to prove Light's innocence would be if Light never left his sight. 24 surveillance of a possible mass murderer in order to catch him in the act sounds perfectly reasonable. Light completely agrees to it. But instead of simply putting cameras in every room and not allowing Light to leave the premises, L handcuffs them together. Everyone in the room who saw and heard the idea thought it a bit ...odd.
Misa-Misa: two boys...that's gross! Does Ryuuzaki(L) swing that way?
When L decides to walk around the hotel he drags Light like a dog. I've also noticed from other anime (Ex: X-1999) that writers and artists often use the imagery of red string, rope or handcuffs to illustrate that two character's fates, lives or hearts are bound together.
There's one scene just before L's eminent death in episode 25 that is so oddly homo-erotic, out of place and unnecessary to the furthering of the plot that I wondered just how the creators planned to justify it. For the uninitiated, Light finds L standing alone in the rain on the roof one day and joins him. Afterwards they're soaked and go to dry off. Both are perfectly capable of drying themselves but L offers of help Light dry off, then is that wasn't enough decides to give him a foot massage. Even stranger, Light allows this and dries L's hair as he rubs. What makes the scene worse is the soft piano solo in the background. For a few minutes it's like you're watching a completely different show.
I mean despite all the "quality time" they've spent together throughout the series, L has always believed Light was KIRA, and Light has been plotting to kill L since episode 2, so the scene in the rain and the massaging is especially strange.
L's dramatic but brief death scene is also noteworthy. Rem (Misa-Misa's shinigami) finally decides puts an end to L by writing his name in a deatnote. A deathnote induced heart attack forces L to fall out of his chair. When Light realizes L will die in the next minute, looking stunned when he shouldn't he rushes over to catch L as he falls. As they both crash to the floor, Light holds a frightened L close. As L succumbs to heart failure, Light's evil smirking face is the last thing he sees. Light watches as L slowly dies in his arms at which point Light's smirk quickly fades and he's left holding the corpse of his only friend. Afterwards Light screams bloody murder as if truly grief stricken. It was brilliant acting, but at the same time you have to wonder how much of it is really an act.
L of course is Light's main opposition through much of the series. So it would be pretty safe to assume that he
would be nothing short of ecstatic when L finally meets his end. But instead, for the next episode or so, Light
is shown as being sullen and even sedate. When others are talking to him, while working on the KIRA case,
or on a date with MIsa his eyes are just flat and dead. His mind wanders to L and he conjures up images of him
as if he was still alive and sitting right next to him.
When Light is forced to match wits with the combined prowess of both Mello/M and Near/N, he vehemently dismisses their intelligence. He constantly compares them to L and how they can never been as good, as smart or as worthy a foe as L was. Light believes this so whole-heartedly that his perfect planning and impenetrable defense finally slips and he is caught, shot and humiliated.