The Lifestream

"Why do we stay in the cradle? Why do we provide suffering to our little heart? Our star did not leave us...did not leave us...our star did not leave us...did not leave us. The pulse of veins flowing in the earth. Faint...faint pulse, heart leading to death. And the weak life return to the planet. Is it necessary to sacrifice the soul? Why do we stay in the cradle? Why do we beg for mercy? In the fatal earth?"

—--The Promised Land, Final Fantasy VII Advent Children.

A specific form of the afterlife, a nexus where souls/hearts/spirits go to die, and sometimes where they come from. This is sometimes implied to be a physical place, or maybe in another dimension. In Western media, has parallels to Eastern religion aside from occasional artsy substitutions, and a very good way to refer to the concept of life and death when a series may not allow you do to so without offending Media Watchdogs by portraying Heaven. Naturally very common in anime.

The Trope Namer is Final Fantasy VII.

See also Sentient Cosmic Force. May be part of the conflict in a setting where Harmony Versus Discipline is used. Not to be confused with AIM's Twitter-esque status update feature.

Examples of The Lifestream include:

Anime & Manga

The Galaxy Cauldron from the Sailor Moon manga.
Something similar is seen in the Anime Mushishi. The Lifestream is good for life in general, but it's dangerous to look at for long periods of time. Why? Well, let's just say we hope you don't terribly miss the use of your eyes.
The Akasha in Nasuverse is the place where souls of the deceased are recycled to create new souls. However, it is also described as "the root of everything", as the concept of time does not apply; if a conscious being somehow manages to enter, it is basically The Nothing After Death. Akasha is also where the magi strive to reach, as "connecting" with Akasha allows the use of True Magic, which are miracles beyond the scope of current science or magecraft, such as Zelretch's alternate dimension travel.
In the 2003 anime version of Fullmetal Alchemist, the souls of people who die in our Universe is converted to energy that fuels alchemy in their Universe. Ouch.
In End of Evangelion, there is a brief scene where Shinji Ikari is watching all the souls gathered from Third Impact flowing around in the Black Moon like a stream of water. Not really a surprise since the entire movie is a Downer Ending.
Kaiba has an interesting physical version of this: people's memories are gold-colored "roe", and ones that are no longer in use for whatever reason (often death), if they aren't stored in special facilities (or if those facilities are destroyed), will float up into outer space, so there is an enormous river of memory roe flowing through space.
The Primary Village serves the same purpose in Digimon. All slain digimon's data recollects itself here as eggs.
Chrono Crusade also has this, referred to as, "The Astral Line".
The rukh from Magi Labyrinth of Magic, which comes in white or black. White rukh is created from those who live within life's flow and follow fate, and is drawn to positive emotions. Black rukh is created from those who try to defy that flow and destiny, and is drawn to negative emotions like malice.

Comic Books

Comic book example: The Speed Force in The DCU is sometimes portrayed like this.
- In essence the Speed Force acts as the Valhalla for all speedsters who use it directly when they die. It's not completely certain why this happened but it's believed that when Barry Allen was hit by the lightning bolt that gave him his powers that it simultaneously made him the first user of the Speed Force and sending the Speed Force throughout time and the multiverse. Since Barry is the first person to have the Speed Force every step he takes causes the Speed Force to grow making it it's own dimension.
The Keywork in The Amory Wars is a subversion: the souls are tortured and used as a fuel source for the entire galaxy. In fact, there is an entire race, called Stars, who were created just for there to be more souls to burn.
There was an issue of Stormwatch (The Authority's predecessor) where it was revealed that Heaven and Hell were cosmic siege engines locked in an endless war, powered by the souls of the dead. There was a bar next to a nuclear testing range with a wall of photos of physicists who'd ended their lives at ground zero of a nuclear blast to deny either side their soul.

Film

In the Star Wars mythos, the Force is described as working like this, and characters who die are often described as becoming "one with the Force."
In Final Fantasy the Spirits Within, the Earth is described as having a Gaia which is essentially the Lifestream from Final Fantasy VII with a different name.
In Avatar, the spirits of the departed live on inside Eiwa—and their memories are accessible if you plug your ponytail into a tree.

Literature

The Halls of Mandos in The Silmarillion.
The computer system that runs the Afterlife in Paul Robinson's Instrument of God.
The Pendragon Adventure's Solara.

Live Action TV

This performance by Harry Belafonte on The Muppet Show.

Religion & Mythology

In some versions of Buddhism, souls go to the "Bardo" for a time-out between incarnations. Several interludes in The Years of Rice and Salt, an alternate-history novel by Kim Stanely Robinson, are set in the Bardo. The Chinese "Di Yu," or "Earth Prison," is similar to the Bardo although it is usually translated as "Hell" and there is some tormenting of sinners in the lower levels.

Tabletop Games

The "Rebirth Into Death" setting in All Flesh Must Be Eaten poses that all life is ultimately part of one overarching source of life. In the beginning, living creatures were born randomly, but once humanity evolved, some souls retained their consciousness after death and figured out how to rig the life force (effectively creating chains of reincarnation). They stopped paying attention to it when some of their number worked out how to get into Paradise, and the system is breaking down - life energy is now going into corpses. Cue the Zombie Apocalypse.
Exalted: Creation always have the number of souls necessary to animate living beings in it, since the Ewer of Soul always provide exactly that much. The problem that Autochthon—a machine-god who is also a self-contained world—face in his self-imposed exile is that he need to eat souls (to put it simply), and he's dying because he can't get fresh ones.
- Note that there's no Lifestream in a traditional sense; souls normally reincarnate, thus they enter Creation but doesn't leave it. The only way souls meet Final Death is by falling into Oblivion. The Neverborn want to toss everything, themselves included, into Oblivion.
Dungeons & Dragons have the (rather poorly-defined) Incarnum. It's either soul or Life Energy, and the lack of it causes stillbirth. Which happened when a dragon by the name Ashardalon sat on its source, gleefully omnomnom-ing it. Some heroes eventually dealt with him, but the source of Incarnum was cracked (or something), causing Incarnum to be available-as-powers like magic or psionic. When it's materialized, it looks like light-blue sands.

Video Games

The Aether in Aion. It's rather disturbingly also used as an all-purpose tool to power all kinds of things, such as flight, magic, armor, weapons, and force fields.
Used in several Final Fantasy games:
- The Lifestream in Final Fantasy VII, which is the Trope Namer.
- The Gaias in Final Fantasy the Spirits Within. In fact, the entire plot of the movie is actually that of the battle between Earth's Gaia and one from a dead world, its souls having been driven insane after drifting through space for untold aeons until slamming into Earth.
- Final Fantasy IX has a similar conflict running behind the scenes; the Evil Plan is to prevent the souls of the people of Gaia from reincarnating, so the souls of the people of Terra can replace them.
- The Farplane in Final Fantasy X and Final Fantasy X-2. A young Spiran genius named Shinra speculates on its use as a power source, and as it turns out, that wide-eyed boy's descendants developed space travel, found a planet with a similar afterlife, and made his dream come true. I'm talking about the Planet from FFVII.
- The basic motivation of the Big Bad in Final Fantasy XIII is to turn the world's remaining human population into this in order to get the attention of his long-vanished god.
Glaive Le Gable in Wild ARMs 2.
Kingdom Hearts has Kingdom Hearts.
In the game Darwinia, each creature has a digital "soul" that rises into the sky and merges into a soul collector which hovers over the world when they die, and which feeds them back down as a rain of souls on another location, where they go on to be processed into new creatures. In this manner, even the souls of The Virus that infects the digital world of Darwinia can be reincarnated as clean darwinians. One virus creature permanently destroys the souls of those it eats, however.
The Chroma in Fahrenheit a.k.a. Fahrenheit (2005 video game). While its nature is not fully explained (which might place it into The Force category instead), it is mentioned that this is where all living things derive their life energy from, hence, a person with high concentration of chroma in their body (like Lukas) is extremely energetic, like, bare-handedly-fighting-off-a-police-squad-and-then-jumping-atop-of-a-moving-train energetic.
In Shin Megami Tensei: Digital Devil Saga II, the Sun holds the "data" of dead people until they reincarnate. Or, at least, it used to, before something went horribly wrong...
Bioshock 2: ADAM has become a variant. Once a human Splices with it, their genetic blueprint, personality, memories, and powers are imprinted in the substance contained in their bodies. Sophia Lamb wishes to fuse her daughter with the aggregate genius of Rapture to make her the first "Utopian".
The Sea of Souls in King's Quest VI.
How Mantra is portrayed in Asura's Wrath. Controlled by Chakravartin, a God who's a major asshole that thinks he does good deeds by testing the demi-gods that use the mantra he bestowed upon them by sending monstrous gohma to try and kill them.

Webcomics

In Twokinds, Dark mana is actually life-force energy siphoned from the planet and people. It's used to cast shadow magic.

Western Animation

The Allspark in the Transformers series. At least, as far as the Unicron Trilogy is concerned. In Beast Wars and Beast Machines, it was called the Matrix (which is also the name of a MacGuffin that isn't really related to it.)
- The name is changed to "The Well of All Sparks" in Transformers Animated, mostly because in this one the Allspark is an actual, physical item. This may or may not go for the movieverse as well.