In the new movie which takes place 10 years after the fateful battle between Yagami Light (Fujiwara Tatsuya) and L, 6 volumes of Death Note are scattered in the human world thus causing new chaos when a series of murders start happening. The key characters in the new movie include Mishima (Higashide Masahiro) who is very knowledgeable about the Kira case, Ryuzaki (Ikematsu Sousuke) who is L's successor and the terrorist Shion (Suda Masaki) who is a fan of Kira. Toda Erika will also be back to play Amane Misa while Ryuk's voice will be played by Nakamura Shido again.
Although L will be featured in the new movie, he will appear for just 3 minutes to share his thoughts on why he used the Death Note to defeat Yagami. As to how he will appear, it will only be revealed in the film. Matsuyama commented that L was a memorable and signature role for him but given the gap and his current physical and mental condition, it would be too much for him to act as L for longer than this time. The producer Sato Takahiro commented that L's return in the new movie is a fan service and intended as a proper "handover" to his junior Ikematsu who comes from the same agency as him and plays L's successor, Matsuyama was then invited to come back to play L again.
Sources: Cinema Today / Oricon / Eiga.com