In works that focus on the conflict between Heaven and Hell (which to be fair, includes most works where Heaven and Hell appear as opposing sides) this will be the ultimate goal of Hell, and is usually kept from happening by an Enemy Civil War or other big conflict among the demons, with the major threat being some ambitious demon or other villain seeking to unify them. Oftentimes, invasion of Heaven is an Evil Plan that the heroes need to stop before it comes to pass, similar to Hell on Earth.
But for those times when things truly go From Bad to Worse, the demons will launch an all-out onslaught against Heaven, seeking to corrupt or destroy the Council of Angels, the Fantasy Pantheon, the Big Guy Himself, and even sending every good soul to hell. Unless The Armies of Heaven are there to stop the advance, the heroes now have the unenviable task of stopping everything from being destroyed (unless God and Satan Are Both Jerks, and the protagonists are Nay Theists and go all "A Plague on Both Your Houses, let's Pass the Popcorn and nuke whoever survives"). Since situations like these are nearly always Grand Finale situations, they are usually big spoilers. Bonus points if the heroes and The Armies of Heaven fight side by side, or the heroes reunite with another hero character, who earlier was Killed Off for Real, and get to fight alongside them one last time.
- DC had this happen with Asmodel, the treachous leader of the Bull-Host of Angels who wanted to succeed where Lucifer had failed and overthrow God, or "The Presence" as he's known in DC. Despite the interference by the Justice League and his arch-enemy Zauriel, Asmodel managed to fight his way to the Presence's throne room... only to find it empty, except for Zauriel. Zauriel reminds Asmodel that the Presence isn't contained to a throne (it's just where the angels go to commune with him), he's part of the very foundation of existence, and thus, there is, and never was, any way that any sort of rebellion against Him can succeed.
- The Space Opera version occurs in Final Crisis with the New Gods:
Darkseid: There was a war in Heaven, Mister Turpin, and I won.
- This is attempted in Ghost Rider's "Heaven on Fire" arc since most of the angels are out of commission, but it still fails horribly as the Spirits of Vengeance fill in for them, resulting in much demon ass getting kicked.
- Subverted in Lucifer: Hell first defeats the Lilim, who are besieging Heaven. Although Heaven surrenders to Hell, this is demonstrated to be the correct moral outcome, since the leader of the Hellish host Christopher Rudd is redeemed.
- This is Hell's grand plan in the Spawn series, with Hellspawn in charge of gathering souls for Hell's army.
- Referenced in Dogma, insofar as with the sudden removal of God from the picture, Metatron explains that one of the obvious guesses is out of the picture because if this were the work of Satan, he'd "have made his move to conquer Heaven by now" and instead they're as surprised as everyone.
- The Beginning After the End has a fantasy variation of this wherein Agrona (the resident Maou the Demon King and Satanic Archetype) and the Vritra Clan seek to conquer Epheotus (the realm of the Asuras from which they were exiled from generations ago) with their army of Vritra-blooded mutants amassed from the populations of both Dicathen and Alacrya. It is worth noting however, Alacrya (the land the Vritra were exiled to and have since become the Supernatural Elite of) is not the equivalent of Hell and is just another continent with its inhabitants being as much victims of the Divine Conflict as the Dicathians are given how God and Satan Are Both Jerks is in full effect with the Asuras of Epheotus being just as bad as the Vritra themselves. Amusingly, it is brought up among Arthur and his allies that letting Agrona invade Epheotus would be the only way to end the conflict by having both sides obliterate each other through Mutually Assured Destruction, as prior experiences have shown a direct war against the Asuras would be a complete slaughter.
- Inverted in The Boy with the Chainsaw Heart, where Heaven has invaded Hell and is making slow but steady progress in conquering more and more of it. Since God and Satan Are Both Jerks, this is not as good a thing as it may seem.
- Wendy Alec's The Chronicles of Brothers series, a series of Christian polemic novels about the in-fighting between the brethren Gabriel, Michael, Christos and the black sheep of the family, Lucifer. The aforementioned Lucifer tries this on more than one occasion, only to be humiliatingly bitch-slapped by his brother Christos and the lads. As Mrs. Alec's novels follow pretty much exactly the Christian perspective and what is "known" (in the Bible and related sources) about the nature of Heaven and Hell and their denizens, you wonder why Lucifer even bothered... it's in the Bible, you'll never win...
- Discussed in the The Crew of the Copper-Colored Cupids story The Dark Cabaret when the characters learn that the angels are fighting in some sort of supernatural war. Sneernobiel, however, cryptically states that they're fighting something worse than demons.
- The Great Divorce: Played with in a very strange way: the only things that ever come out of hell into heaven are ghosts, and ghosts are too unreal to do any damage. However, some of those ghosts, in one way or another, have the motivation (but never the ability) to bring Hell into Heaven in one way or another, ranging from explaining Hell to the Persons in Heaven, to trying to convince the Persons in Heaven to transform Heaven to look more like Hell, to simply screaming in hatred at anyone in Heaven.
- John Milton's Paradise Lost is the trope codifier/forerunner by depicting Satan's rebellion against God.
- Paradise Lost inspired a subverted example of this trope, the His Dark Materials series, where The Legions of Hell are actually the good guys.
- A non-Abrahamic example appears near the end of Percy Jackson and the Olympians. As the Battle of Manhattan races to a close, our heroes take a Climactic Elevator Ride up to Olympus to make a last attempt at stopping Kronos. It's pretty simple to find him-he carved a swathe of destruction through the city. Given its previous appearances as a Crystal Spires and Togas-type place, it's jarring and sets the dire tone for the fight well.
- In Sandman Slim the original fallen angels find out what a bad idea it is to rebel against God. They get curbstomped and dumped into Hell, where they've building up a mighty army to invade Heaven... so that they could get massacred (in a sort-of "suicide by cop", in their view). Heaven is way too strong and would kill any army of theirs in seconds, and the rulers of Hell know this but being in Hell is so boring and meaningless that they would rather be obliterated than stick around much longer.
- Attempted in the backstory of "The Snow Queen" — the devil invents a magic mirror that will make everything look hideous, and he and several of his student demons decide to take it to Heaven so that they can mock God and the angels. The mirror breaks before they can get high enough.
- The Sandman (2022): In the Season 1 finale, "Lost Hearts", an ambitious Demon Lord proposes that Lucifer invade the Dreaming, the mortal world, and ultimately the Silver City. Lucifer doesn't answer, but confesses to being intrigued.
Lord Azazel: Since none of us may leave Hell, we may as well expand its borders until Hell is all there is.
- In Supernatural, this seems to be Lucifer's PR to his demon mooks after they release him and start the Apocalypse. Meg cheerily taunts a captured Castiel that they're going to win against the angels and invade Heaven itself. In reality, Lucifer wants the demons to have no part in his plans and considers them worthy of annihilation.
- Much of Bathory's early material has this. Examples include "Armageddon" and "War" from their self titled debut, while Blood Fire Death features "The Golden Walls of Heaven" and "Dies Irae"
- Slayer's "Hell Awaits" is either a literal description of this or a metaphor for iredeemable damnation.
- Venom's 20 minute epic entitled "At War With Satan". It Book Ends with Heaven's surviving armies and archangels recuperating in Hell and planning to retake Heaven.
- From their influential album Black Metal comes the track "Heaven's On Fire"
- According to the La Llorona mythos believed in by Miami street kids, a demon attack went down in Heaven, and God had to flee. No one has seen Him since, and the angels have to fight off the demons in the meantime. Demons have found a way to invade our world, and the angels who aren't defending Heaven have come to Earth to fight them.
- In Dungeons & Dragons, if the Blood War between the demons and the devils ever ends, the Upper Planes can look forward to a full-scale war with the fiends as they launch an invasion. When the Blood War did end in the Forgotten Realms setting...this didn't end up happening. Asmodeus permanently shoved the Abyss into a corner of the Elemental Chaos that couldn't reach Hell, used the resulting chaos to ascend to full-on godhood by eating Azuth the God of Wizardry, and then settled in and started the clean-up process.
- Exalted: In Return of the Scarlet Empress The force of the Demon City or rather, just the Ebon Dragon manages to invade Yu-shan and kills all the Incarnae. What they don't expect, though, is that the death of the Incarnae unlocks the god-tier powers of all Celestial Exalts.
- In The Ring of the Nibelung, Alberich boasts that he will invade Valhalla from Hella once he recovers the Ring.
- This is the final act in the first campaign of Diablo III. Diablo, having become the Prime Evil — the embodiment of all Seven Great Evils in one being — and the sole ruler of the Burning Hells, leads a massive demonic invasion of the High Heavens. The angels are unprepared for an attack of this magnitude and are quickly overrun, some of them being outright corrupted. The player helps drive them back and defeats Diablo at the very top of the Crystal Spire. Supplemental materials explain that similar attacks have occurred in the past but never made it past the Diamond Gates, usually due to demonic in-fighting weakening their forces.
- This is what the last few levels of Disgaea: Hour of Darkness are based around. You're the one controlling The Legions of Hell. It turns out to have been a part of a plan cooked up between the guy in charge of heaven and Laharl's father to make sure he ends up as a Noble Demon.
- In Disgaea D2, the Netherworld's environment is being rapidly taken over by a specific type of flower that only grows in Celestia, and they assume the inversion is happening. The truth is not so straightforward.
- In Disgaea 3, to the frustration of Raspberyl while being a delinquent teacher, her demon students think she's doing this with a harmless trip to Celestia.
- While it doesn't happen on-screen, one Non Standard Game Over of Disgaea 4 has Valvatorez and company fighting an extended war against everybody in existence (including God).
- Doom Eternal has demons invading Urdak as the Khan Maykr seeks to awaken and bind the Icon of Sin to destroy Earth, only for the Slayer to disrupt the ritual that would have given her control over it. Though the Slayer takes out his share of the demons in the midst of opening a portal to get back to Earth to stop the Icon of Sin, when the Khan Maykr is finally defeated, the demons waste no time in overrunning the place, as the deal with Hell that brought about the making of Argent Energy has been rendered null and void. But since the Maykrs and especially the Khan Maykr have been revealed to be little better than the demons themselves at this point, the Slayer could not care less about this outcome.
- The driving plot of Painkiller. Lucifer is using Purgatory as a staging ground from which to launch an invasion of Heaven, and Daniel Garner is Heaven's hitman chosen to send Lucifer's generals back to Hell to slow down Hell's armies while Heaven prepares.
- While it doesn't happen literally, this symbolically happens in Persona 4, when the Investigation Team must go through the Shadow-infested dungeon of Heaven, where Nanako is being held.
- In Planescape: Torment, Trias the Betrayer was planning to organize an army of fiends to do this to get the gods to wake up and deal with the Blood War, which led to his incarceration under Curst.
- The Sphere is an enormous alien vessel in Prey (2006), not quite Hell (although a lot of humans have been abducted, tortured and mutilated there). But it's still a late-game surprise when the Sphere's Keeper sends an invasion force into the Cherokee spirit world and Tommy and his Grandfather's ghost must repel them.
- This is what happens in the True Demon Ending of Shin Megami Tensei III: Nocturne, as the protagonist joins forces with Lucifer against YHVH himself in a bid to stop the cycle of apocalypse and create a new world.
- In Super Paper Mario, an army of Skellobits from the Underwhere invades the Overthere, where an army of Nimbis rises to fight it. In a twist, said Skellobit army is not affiliated with the leader of the Underwhere who is actually raising a daughter with her Overthere counterpart, but with a recently-released Sealed Evil in a Can who serves as the chapter's boss.
- In Titan Quest: The Immortal Throne, when you reach the Elysium you find out that the heroes there are fighting back the hordes of shades and demons serving Hades, which has gone mad with power. Odder than the standard example because Elysium is still part of Hades's kingdom. The final part of Titan Quest also qualifies as a variation; you have to prevent Typhon, the most fearsome of the Titans from invading Mt. Olympus.
- In the Lady Spectra & Sparky storyline "Demon War", archfiend Melado and his minions invade the Limbo-like afterlife realm of "Rha-Sha-Shama".
- Achieving this is the stated end goal of the IFCC Directors in The Order of the Stick, as outlined in Strip #633. "The blood of angels will flow like rivers, and we will gather around great dispensers of it to discuss the previous evening's televised entertainment!"
- There's No Light In Heaven: A creepypasta story revolving around a woman who dies in a traffic accident, only to find the afterlife (apparently a rather cartoony version of Heaven originally, there's even a mention of the remains of St Peters podium next to the ruins of the Pearly Gates]] a dark, dismal ruin haunted by demonic abominations who attack and feed on the souls of anyone who ends up there. However, it's later revealed by one of the surviving souls that these aren't demons in the traditional sense: they were apparently originally angels who became "corrupted" somehow after visiting Earth, though it's not explained in detail.