About Death Note
Death Note is a Japanese manga series created by writer Tsugumi Ohba and illustrator Takeshi Obata. The series centers on Light Yagami, a high school student who discovers a supernatural notebook, the titular "Death Note", dropped on Earth by a shinigami (death god) named Ryuk. The Death Note grants its user the ability to kill anyone whose face they have seen, by writing the victim's name in the notebook. The story follows Light's attempt to create and rule a world cleansed of evil using the notebook, and the complex conflict between him and his opponents.
Death Note was first serialized in 108 chapters by Shueisha in the Japanese manga magazine Weekly Shōnen Jump from December 2003 to May 2006. The series was also published in tankōbon (paperback) format in Japan starting in May 2004 and ending in October 2006, and since then has been translated internationally. The series was adapted into live-action films released in Japan on June 17, 2006, on November 3, 2006, and on February 2, 2008. The anime series aired in Japan from October 3, 2006, to June 26, 2007. A novel based on the series, written by Nisio Isin, was released in Japan on August 1, 2006.
About Near, Mello & L
L is the primary antagonist of the series, L is the world's top-rated detective and tasked with tracking down and arresting Kira. As such, he is Light's arch-enemy. He often takes drastic strategies to confuse and force the hand of his opponents, and his disheveled appearance disguises his brilliance. He enjoys sugar, and in nearly every scene including him, he is found eating cake or confectionery and drinking highly sweetened tea. His real name is L Lawliet.
Near is a calm and stoic character that appears in the second half of the series. In the anime and manga versions, Near is a primary candidate to become L's successor and calls himself N during the course of his investigations. He shares a number of similarities with L. Much like how L plays with things such as sugar cubes and forks, Near is frequently shown playing with toys or hair, and he is constantly shown sitting in an unusual manner. After L's death, he was asked to join forces with Mello, who refused (it is explained that Near lacks the emotional insight to beat L, while Mello is too emotional and impulsive). Near then gained the support of the Government of the United States and formed the Secret Provision for Kira (SPK). In the 'extra' manga story, set after the end of the series, Near states that, while he respects Light's drive for justice, he can never find his 'Kira' actions excusable. His real name is Nate River. :In the film L: Change the World L grants the name "Near" to a Thai boy who is a mathematical genius; L intends for Near to succeed him.
Mello, a character present in the anime and manga versions, was an orphan who grew up with Near and Matt in Wammy's House, Watari's shelter for "gifted" children. Like Near and Matt, Mello was one of the candidates to become L's successor. Similar to L's fondness for sweets, he is often seen eating bars of chocolate. Although Mello is quite intelligent, he often lets his emotions get the better of him. His goal in life is to surpass L and Near. His real name is Mihael Keehl.
Taken from Wikipedia.