The Leaf village is the ninja village of most of the major characters in the Naruto story. The dead ninjas in this village had mainly been protagonists with varying degrees of reputation. The first and second "Hokages," or leaders, in particular were responsible for establishing the Leaf village prior to the start of the Naruto story. The fourth "Hokage" is the main character's -- Naruto's -- father. He was responsible for triggering the main plot element of the story: the sealing of the demon fox inside Naruto which was also the subsequent cause of the "Hokage's" death.
The Leaf village has allied ninja villages such as the Sand village. The Leaf and the Sand work in tandem for numerous ninja missions -- some of which ended in major character deaths. For example, elder Chiyo of the Sand village had joined Naruto's team to rescue Gaara, the leader of the Sand village. After realizing that they were too late to prevent the death of Gaara, Chiyo used a forbidden self-sacrifice ninja technique to revive the dead Gaara. Certain antagonists are later considered as protagonists after the character's last moments; Pain from the Rain village used a godlike technique to revive all the Leaf ninja he had killed in exchange for his own life.
Most of the Naruto story antagonists come from outside the Leaf village. The renegade ninja group, "Akatsuki", are de facto without a village; each ninja had rebelled against their original village. The crossed out village marking on their ninja headbands symbolizes this rebellion. As of the latest 2010 story arcs of Naruto Shippuden, all but three members of the original Akatsuki died in battle. Main Akatsuki antagonists include Orochimaru: a former Leaf ninja who died after Uchiha Sasuke's rebellion against him.
As of the March 2011 Naruto Shippuden story arc, most of the dead characters had come back to life as both willing and unwilling antagonists. This is because of a forbidden reanimation technique used by Kabuto, Orochimaru's disciple. This technique uses living bodies as sacrifices to bring back dead souls. These undead bodies have all of the dead ninja's abilities intact and are impervious to physical damage. The March 2011 arc depicts a war between the alliance of all ninja villages and the undead ninjas from this technique.