Death

Death is the all encompassing force that eventually affects all humans, ghosts, snakes, and several other beings from Ninjago and the other realms. It is the cessation of the functions that allow a living or un-dead being to continue to exist in the living world. It is the only known way to gain entry into the Departed Realm.

Known dead characters:
Notice: Everyone in Ninjago, or any realm, is, has been, or will someday be on this list.

Humans

 * Dr. Julien (formerly resurrected by Samukai, now departed once more)
 * Garmadon
 * Captain Soto (formerly; resurrected by the Mega Weapon)
 * The rest of the Destiny's Bounty crew (formerly; resurrected by the Mega Weapon)
 * Dilara
 * Nya (In an alternate timeline)
 * Cliff Gordon
 * Several Elemental Masters
 * Several Cloud Kingdom monks
 * Several other humans

Skulkin

 * All Skulkin are undead except Samukai, who was sent to the Departed Realm

Serpentine

 * All Anacondrai except Pythor
 * Anacondrai Serpent
 * The Great Devourer

Stone Army

 * All except the Giant Stone Warrior

Nindroids (Overlord Faction)

 * All except some in Kryptarium and some, who became Cyrus Borg's Security Droids.

Anacondrai Cultists

 * All except Clouse and Skylor

Cursed Ghosts

 * All Ghost Warriors who were imprisoned in the Cursed Realm except Clouse

Djinn

 * All except Nadakhan

Beings who ascend Death
Additionally, scattered across the Sixteen Realms are multiple beings of massive, nearly omnipotent power and influence whose ancient power and origins prevents them from suffering death in the ways mortals understand it. These beings can at best be so damaged that they only exist as dormant spirits who are too weakened to form a consciousness. Even afterwards, however, the power and essence of these beings can and/or will remain in the realms of the living as a byproduct of their cessation.
 * First Spinjitzu Master (Left behind the essences of Golden Power, Energy, Creation, and Destruction after his death)
 * The Overlord (Left behind the essences of Darkness and the substance Dark Matter)
 * The Preeminent (Left behind the essences of cursed Ghosts after her death)

Realms of the Deceased
In all of Ninjago and the Sixteen Realms, there were a total of three known realms for the dead to continue to dwell after their passing. Of the three, the Departed Realm seems to be where the dead are naturally supposed to go, as when a being whom was sent to the other two is destroyed, their spirit will move on to the Departed Realm.
 * Departed Realm (for all denizens of all Realms)
 * The Underworld (for fallen warriors whom were disgraced in battle, and don't accept or realize their passing)
 * Cursed Realm (for those who are cursed, or die with a wicked heart; destroyed)

Returning to Life
Death can be also thwarted, but the ways that this can be accomplished are extremely dangerous and unstable, as it goes against the natural order of the world. Likewise, the consequences of such methods on users can prove too dire or even worse than death itself. These are some ways to trick death:
 * Resurrectea (Temporary postponement of Death)
 * Rift of Return (Requires powerful magic from the Yin-Yang Eclipse to sustain)
 * The power of the Yin Blade (Places victim into a state of ghost-like limbo)
 * Being wished into the body of another living being by a Djinn King (Possession of another person)
 * Killing one's murderer with a Departed Blade
 * Magic
 * Escaping from the Cursed Realm or Underworld (Escapee is left in an undead state of being, either skeletal or cursed)
 * Resurrection by the Mega Weapon (Massive energy toll on user required)
 * Reversing time on the corpse of the deceased (Negated by Tomorrow's Tea)
 * Escape from the Departed Realm (Requires a massive amount of catalyzed magic to sustain indefinitely)
 * Imprisonment in the Djinn Blade (Indefinite, unconscious limbo for all eternity)