Yes, L does die in the Death Note manga.
Yes. L's demise is a crucial part of the story. It occurs due to the intense battles of wits and strategic moves by the various characters.
Chapter 346, "Formidable Soldiers and Brave Generals, One Against Three, Reason Behind the Beast Tide", is the clearest early answer because it turns Redwood Ridge's situation into a concrete plot event. A useful checkpoint is the way the scene starts with The beast tide in the Arrow Bamboo Forest has been going on for so... and follows through with This is the core reason he could be appointed as Colonel of the....
Chapter 341, "Moao's Nine Garrisons, the Inspection System and Zhenyu, Li Hu and Hong Yuru (Part 3)", is the clearest early answer because it turns Lu Yang's situation into a concrete plot event. The chapter turns that into something concrete by moving from Of course, just this alone is not enough to deal with He Wuyang. to Not to mention the future annexation of Baisong Camp, just the 24....
Chapter 273, ""Justice Will Eventually Triumph Over Evil", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. The chapter gives readers a real answer by opening on Jiang Li, who was reading a book, suddenly jumped in fright.
Chapter 18, "Criminal Law stipulates that kidnappers will be imprisoned.", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event. It opens with In the corner, a girl in a black dress sat quietly, holding a glass...
Chapter 89, "Brother He, how can you be so unreasonable too?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Director Sun took a step back, "What's the rush?
Chapter 135, "Lai Fu is Missing!", is the clearest early answer because it turns Missing's situation into a concrete plot event.
Chapter 312, "Charity Gala Invitation", is the clearest early answer because it turns Wen Jiaojiao's situation into a concrete plot event. Early on, Du Sang's dinner party wasn't urgent, because it was still a month.... By the end, Why the hell didn't they send me an invite?!.
Chapter 340, "Seclusion, Growing Yu Generation, Family Banquet, Rapid Development", is the clearest early answer because it turns Star's situation into a concrete plot event. Early on, But unexpectedly, at this very moment, the solemn and sacred.... By the end, The last time Nong Ying carried the Second Prince, she wasn't paying....
Chapter 108, "Without accumulating virtue through words, calamities of bloodshed will only increase, not decrease.", is the clearest early answer because it turns Su Yinwan's situation into a concrete plot event. It opens with In a glamorous Michelin three-star restaurant, Su Yinwan and Shang...
Chapter 346, "Elite Warriors, One Against Three, The Cause of the Beast Tide [10,000-Word Chapter, Continued Tomorrow]", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from Nowadays, any of these six armies alone, placed five years ago, would... to Thus, in Great Xia, it's a comparison of who breaks through more....