ote: i got all of this information from)http://www.absoluteanime.com/death_note/index.htm
Light is a typical seventeen year old, except that he's a genius. While looking out the window of his class one day, he sees a black book fall out of the sky. After school ends, he goes over and picks up the book, with the words "Death Note" written in a creepy font. While looking over the book, he reads that the book will kill the person whose name is written in it.
At first, Light doesn't believe it, but ends up taking the book home, where he writes down the name of a criminal that was on TV. As the book said, the man died. Light realizes his amazing possibilities, and starts killing criminals who have done major or minor crimes, or people he feels the world will be better off without.
After a few days of messing around with the Death note, he is confronted byRyuk, the former owner of the Death Note. Ryuk gives him a lot of information regarding the Death Note. But even despite his scary appearance, Ryuk is crazy for apples, which Light supplies him with.
Unfortunately, because most of the criminals are dying of cardiac arrest, the police get involved, and Light, now dubbed "Kira" by the public, is risking himself every time he kills a convict. Another genius, who goes by the alias of "L", is trying his hardest to stop Light, but both always seem a few steps ahead of each other.
Kira lives with his mother, father, and younger sister.
According to Death Note: How To Read 13, his date of birth is February 28, 1986, while Misa's birthdate is December 25, 1984. Thus, he is younger than Misa. His date of death is January 28, 2010, one month short of his birthday. His likes are listed as justice, and his dislikes as evil.
When he starts the Kira case, he immediately begins the investigation withLight. As Light tries to prove his innocence, L gets more proof that Kira is, in fact, Light. He even invites Light the join the Kira investigation in order to gain more evidence against him, but unfortunately Light is always three steps ahead.
L's full name, L Lawliet, is finally revealed in "How to Read 13", which is considered to be the 13th volume of the Death Note manga series. He was born on October 31, 1979, enters the series on December 4, 2003 at the age of 24, and dies on November 5th of the following year at age 25. However, the anime adjusts the years a bit, making L's birth occurring in 1982.
Misa Amane is a model, actress, killer, and is infatuated with the originalKira. Thanks to Kira, the criminal who killed her parents was killed in return. Due to this, Misa travels to Japan to find and meet with Kira.
She has a second Death Note, given to her by Rem. Thanks to having a Death Note, she makes an eye trade with Rem and can see people's names and lifespans above their heads, unless they also possess a Death Note, in which case she only see's their name. That is how she figures out who Kiraactually is, and begins her romance with Light. Things get complicated as it goes on, but I don't want to spoil everything.
Near was raised in an orphanage, and is highly intelligent. Watari was the owner/creator of this orphanage, and due to this all the children in there are highly intelligent, but Near was always at the top. Because of this, Near was chosen as one to possibly precede L if anything happened to L.
Near figured out many of the details on the Kira case thatL didn't find out until it was too late. Due to this, the president of the USA makes Near the leader of an organization that is focused on finding Kira. As with L, Near has no written proof of his real name or any photo's anywhere .Near's lifespan is 434016. In the manga, Near is stated to have been born in 1991, while in the anime it becomes 1994. At the start of the series Near is 13 years old, then he is 17 years old when the series picks up after the time skip. And of course he naturally ages throughout the series.
Mello is like Near in the fact that they both grew up in the orphanage, they're both highly intelligent, and they both had the chance to become the next L. Due to L's sudden death (as well as Watari's), they had to choose on the spot who would become the next L instead of letting L choose.
Mello basically said screw it and let Near have the position, sort of out of jealousy. Mello was always second best to Near in every way. Mello then went out on his own, became the leader of a mafia group, and began hunting down Kira and a Death Note. Instead of giving everything away, I'm gonna end this by saying that Mello loves chocolate bars. And by loves, I mean that you'll rarely ever see Mello without a chocolate bar.
The scar on his face was caused by an explosive that he set off in a last desperate attempt to not get caught by the investigation team, of which had a Death Note and Shinigami eyes that could have killed him before he had the chance to catch Kira.
Mello's real name of Mihael Keehl is revealed in volume 9, chapter 73, pages 62-63 of the manga.
In book 9 of Death Note, it's read that Light's father, Soichiro Yagami asked Ryuuku to give him the Shinigami Eyes so that he could see the names of Mello's accomplices. When he found Mello, it read above him that his real name is Mihael Keehl (these guys have weird names huh?).
In book 7, it is stated that when Mello left the orphanage he said that he was almost 15. In chapter 60, it starts showingKira/Light's progress and it starts out in 2005, like the year it was when it first showed Mello, and then it switches to 2009, four years later, thus making Mello about 19 years old. Also, when it showed Mello's name, it showed his life span as well, which was 502209.
Mello dies at the age of 20.
Note: In the manga, Mello was born in 1989, not 1992 like in the anime, because the anime shifted everything forward by three years.