L [ Creative ] "Justice will Prevail." His personality is supposed to counter Light Yagami, the “genius, pretty boy”, as he is a “genius, freak”. L likes to play around a lot, and is very blunt. He loves sweets (especially cakes), and insists that if he does not sit the way he does, his reasoning will drop by 40%. L seems to be sort of a loner, and trusts no one (except Watari of course). [Quoted from Deathgod.org]
Mikami Teru [ Obsessive ] "GOD?!?!" He is smart enough to understand Light’s thinking, but he doesn’t really contemplate with possible consequences of his actions. He may even be a more crazy Light-follower than even Misa is. He blindly obeys whatever Kira says and truely believes he is a God, going to any lengths to prove his loyalty to Kira. [Quoted from Deathgod.org]
Matsuda [ Optimistic ] "After this case, Lets go out for drinks!" He's not the brightest, but he is willing to risk his life for what he thinks is right. He tends to get confused easily, is a tad naive, and is overly optimistic.
Kira [ God-Complex] "I am the God of this new world!!" Kira is the version of Raito Yagami that is killing all, the criminals in order to create a new world, free of criminals. He is willing to give up everything to reach this goal. By the end couple of volumes, he is nothing but a Crazed Serial Killer with a God complex, but he started off just trying to make the world a better place. But he had a perverted sense of justice.
Matt [ Loyal ] "But it's so boring watching something that never changes..." Matt is only seen for about 13 panels in the whole series, but still has a very distinct personality. He's a good spy despite a tendency to let down his guard, a video game fan, and a smoker. He also is stated in canon to have been from Wammy's orphanage in England. Matt appears to be almost normal, Unlike the rest of the kids from Wammy's orphanage. [Quoted from Broken Heros]
Mello [ Zealous ] "I will become number one!!" Bullheaded and daring to the point of foolhardiness, brilliant, with a permanent chip on his shoulder from years of being bested by his rival. Willing to sacrifice standard scruples and moralities to avenge the death of his hero and win the game of Kira. Also, he's addicted to chocolate bars. [Quoted from Broken Heros]
Misa Amane [ Simple-Minded] "Raito-kun!!!" <3 Misa is compleatly and utterly obsessed with Raito. All she wants is for him to love her. And either she doesn't realize she is being used by Kira, or she just doesn't care. Either way, she is perfectly happy giving up her life in order to make Raito happy. She let go of her morals long ago.
Ryuk [ Fun ] "I was bored..." Ryuk is not at all like the other shinigami around him, he hates boredom and lives for excitement. Only for this reason does he take extreme steps like stealing another shinigami’s death note only to drop it in the human world to test what will happen. Ryuk is pretty scary looking, but in general is harmless, as we can see since he stays out of Light’s way and just observes
Linda [ Happy- go-Lucky ] "Near, come play with us..." Maybe the Least recognized character in all of Death Note. Linda went to Whammy's house and was training to be L, along with Near, Mello, and Matt. She has amazing skills in the arts, which is demonstrated when she drew the sketches of Near and Mello for the Japanese police...She seems like a relativly normal little girl, and doesn't like it when Near is left out. She alledgedly keeps asking Near to play with her and the other kids, dispite his constant refusal. In my opinion, she might even have a small crush on him.
Near [ True Genius ] "..." He is quite weird and also very unemotional. He’s entirely on his own pace. He’s even worse at cooperation than L is. He is even willing to use forceful tactics that are barely within the law. Generally speaking, his personality is dry and he values results above all else. [Quoted from Deathgod.org]
Light (Raito) Yagami [ Just ] "...all you see is people the world would be better off without." Raito is the Main character in the series and has a better sense of justice than most people. Light is different from Kira, even though they are the same person. Raito himself, agrees with L in the fact that Kira must be captured, as proven in the Yostuba ark. Even though he agree's with Kira's logic, he realizes that murder is wrong...