This is a no brainer of course. The two of them are extremely intelligent and heads above their peers. Even when comparing them to the other “smart” characters of the series, they still come up on top in a game of wits.

One is a boy who had the misfortune of being born into a relatively family with a strict father. With the need to adhere to society, more so due to the structure that a cop Dad would no doubt impose, a genius like Light would no doubt feel stifled and trapped as he is surrounded by those that he deems to be mediocre. This environment is no doubt what lead him to exploring ways to relieve his boredom, leading him to find the Death Note and starting the series.

On the other hand, L is someone who was adopted by Watari early on and was given the freedom to explore his genius to its full limits. With the freedom to do what he wants with the genius in his hands, he turns to solving crimes that are normally unsolvable by the police force and this in turns leads to him developing a “moral compass” that eventually leads him to clashing with Light.

Is one smarter than the other? It’s hard to say. But Light did only manage to trick L due to having a slight edge in the supernatural area over him, so it might be safe to say that they are almost equal.

Machiavellianism is a personality type that is defined by modern psychology to be one of extreme cunning, intelligence and pragmatism. The cost of having such a logical mind set can be too much to bear however, as it leads to the person being callous, manipulative and generally uncaring to the consequences that their actions have on the people around them as long as the big picture can be met.

Sounds familiar? This is the character archetype that defines many anti-heroes throughout anime history such as Archer of Fate/Stay Night and Lelouch of Code Geass, and coincidentally both our main characters fit snugly into this role as well. That’s right ladies and gentlemen, there are no heroes within the series of Death Note, just the cruel reality of life.

This behaviour is exemplified by both characters throughout the series as well.

When it comes to Light, look no further then Misa Amane. Just the callous way he treats her and the way he makes use of her affections purely for her Death Note shows that he just doesn’t give a damn about anyone or anything regardless of how they feel towards him.

With L, it’s harder to detect because it’s all done in the name of “justice”, but if you look underneath the underneath you can see that the way he carries out his investigations can be extremely brutal as well. He *did* lock up Light and Misa for days on end with little to no human interaction just to prove a point…

Or more accurately, it’s all just a game to the both of them. As stated, the two are just extremely bored genii who don’t know what to do with their time. They are surrounded by what are basically idiots and dullards who can’t match up to them in anyway, much less have a meaningful conversation with. Quoting a phrase from Byakuran Gesso of Katekyo Hitman Reborn!:

“Everything around me just became scenery.”

Much like anyone would in that situation, they sought to break out of their boredom through any means necessary. L was lucky in the sense that he had the outlet he needed to vent his need to stroke his ego through the many cases he solves around the world. In the end, does he care about those that his case saves? Not really. It’s all mostly done to sate his need for thrills. But at least it’s all for a good cause.

Light wasn’t as lucky. After being basically raised around intellectual inferiors, he found the tool that would make his dull life much more interesting; Death Note. Is it any surprise that he immediately went on a rampage soon after with a flimsy excuse such as cleansing the world of evil soon after?

And when the two found each other, it just meant that the game had two players now, making things all the more interesting.

Light wants to cleanse the world of evil by bring the world into a new era of peace through the order that his godhood will bring to everyone. This is done by killing everyone who he deems to be unfit to exist in his new world, ultimately ending up with a sterile world free of crime for all.

L wants to cleanse the world of evil by solving cases by assisting the police and any other peacekeeping organisation with the help of his super genius. This is done by locking up everyone who he deems unfit to exist in society, ultimately ending up with a sterile world free of crime for all.

*cough*
The core of their ideals is the same; justice. They want to bring justice to an unclean and unfair world by ridding it of evil. The differences between them boils down to the method of execution, not what they think of in the end. The result they want is the same, it is merely the semantics of method that separate them.

If they agreed on what to do together…nothing could stop them.

They could have become the same person, given the circumstances. In fact that’s all it is in the end, circumstances. If Light was found by Watari instead and given the freedom to do what he wanted with his intellect, it is likely that he would have stumbled onto the bumbling police forces of the world and assisted them with their investigations.

If L was born into the Yagami family and raised in the strict and structured family, not allowed to help his father with investigations and being made to adhere to the nuances of society, he might have eventually descended into doing something psychotic like murdering criminals using the Death Note, especially after seeing the failings of his father to achieve peace within society despite his methods.

Light and L are the same person at birth. Their intellect separates them from the normal person in a different way that normal intellect does. Should they have been raised in the opposing backgrounds, Light would be on the side of “good” and L would be on the side of “evil”. At the end of the day, circumstances are what turned Light into a psycho murderer bent on bring the world into a new world order. Circumstances were what led L to becoming anime Sherlock Holmes.

In the end, they are the same.