Align
Wallet After Summer Sale -

I feel like there's room for a "Turns out it's man" joke here somewhere.
Animegx43

I think I know who made all of those stairs in Tartarus.
Poptard
Every pony has fans - Derpi Supporter
Silver Bit -
Diamond -
Wallet After Summer Sale -
Not a Llama - Happy April Fools Day!
Happy Derpy! -
Silver Supporter -
The End wasn't The End - Found a new home after the great exodus of 2012

The Tastiest
@Background Pony #5779
I was joking obviously. It'd collapse immediately, thanks to modern understanding of human needs.

Background Pony #5EDF
@Poptard
if the internet suddenly disappeared, as civilization would die slowly but surely
lolwat? "Dark Ages" already happened, and not once. As you can see, human civilisation still exists.
Background Pony #5EDF
@Evowizard25
Sunset Shimmer accidentally opened gates to Tartarus, Cerberus chased off Sunset Shimmer, meanwhile gates closed.
Mayojar77
The End wasn't The End - Found a new home after the great exodus of 2012

@Background Pony #FD10
Why? Hades is a pretty chill guy, for a guy that's been working non stop since the first living things.
Background Pony #E247
I would be less worried about the prisoners, and more worried about the warden.
LadyChaomii

I always had this idea that Changelings are from Tartarus and they escaped when Cerberus ran away. Twilight didn't find them when she went out looking for escaped monsters because they all looked like normal ponies because changelings.
WanderingPony

There is far more to HFIL than merely one evil.
CyanHide

I bet Arabus is here too.

Maybe even Grogar/Tambelon, if Tartarus is just another name for the Realm of Darkness.
British-Heavy-Metal-Dude

ᗪ乇ㄒ乇尺爪丨几卂ㄒ丨ㄖ几✦
Devils never cry____Dante
Mayojar77
The End wasn't The End - Found a new home after the great exodus of 2012

Every multiverse has a Martin Murtons.
LanceOmikron
Wallet After Summer Sale -
Artist -
Magical Inkwell - Wrote MLP fanfiction consisting of at least around 1.5k words, and has a verified link to the platform of their choice
Not a Llama - Happy April Fools Day!

Because COLORING!!
@Science
Tirek had left them there. The mane six get them out right after re-imprisoning Tirek.
Science
The End wasn't The End - Found a new home after the great exodus of 2012

What are the princesses doing on that other platform to the right?
SBF1
The End wasn't The End - Found a new home after the great exodus of 2012

I've actually thought a bit about this myself. It would make for good story concepts.

Imagine, Cerberus runs off, and Tirek manages to escape and gather up a rile up a bunch of other prisoners to escape as well. Obviously they'd lay low (or at least Tirek would, until this point), but you could have the Pone equivalent of vampire hunters (or the 2E Fighters Guild, I dunno) going around hoisting 'em back for fun and profit.
Verbose
Gold Bit -
Emerald -
Since the Beginning  -

It means you might get to see your mother again, OP.
Background Pony #80C5
@albert19
Ooo that could be interesting, turns out Spike is some kinda prophesied child who will bring destruction to the world. Celestia knowing of this prophecy steal Spike away while he is still an egg in hopes of raising him in pony society will fill his heart with kindness and love instead of hatred and despair.
Poptard
Every pony has fans - Derpi Supporter
Silver Bit -
Diamond -
Wallet After Summer Sale -
Not a Llama - Happy April Fools Day!
Happy Derpy! -
Silver Supporter -
The End wasn't The End - Found a new home after the great exodus of 2012

The Tastiest
@Evowizard25
Not from the being drained of energy, likely, but probably from the secondary effects. It'd be like if the internet suddenly disappeared, as civilization would die slowly but surely. Delicate precision unicorn magic would mean that most advanced machinery would fail between a few weeks and months, infrastructure and eventually buildings would crumble as earth ponies lack the strength to reconstruct, and eventually everyone will starve due to the lack of Earth pony magic to tend the fields and being at the mercy of the weather, who can't even fly or interact with clouds. And losing the internet would be far worse…
Jadefire
The End wasn't The End - Found a new home after the great exodus of 2012

Next up: Krastos the Glue Maker.
Brass Melody
My Little Pony - 1992 Edition
Wallet After Summer Sale -

Gas Loving Banana Boy
Of course there is. There's always someone worse in hell.
Psychopomf
The End wasn't The End - Found a new home after the great exodus of 2012

@LanceOmikron

Prince Pluto really didn't like his inheritance… but someone has to do the job
Evowizard25

@Background Pony #4870
I'd prefer a reformed Chrysalis, thank you very much.

@Bryon
Considering his role and all, I'd wager he must have been lured off or set loose. He wouldn't just wander off on his own. (That'd be both dumb and dangerous.)

@LanceOmikron
Probably deeper then we could possibly imagine.
I mean, Tzeentch has to have someone to talk to while he's imprisoned.
Background Pony #56B7
What if we get a REFORM TIREK episode in season 5.
LanceOmikron
Wallet After Summer Sale -
Artist -
Magical Inkwell - Wrote MLP fanfiction consisting of at least around 1.5k words, and has a verified link to the platform of their choice
Not a Llama - Happy April Fools Day!

Because COLORING!!
Nightmares. Dark Gods. Nameless Things. Immortals. All of those and more are imprisoned in the depths of Tartarus. Is Tirek one of the worst… or is he one of the least?

One wonders who established Tartarus, and who imprisoned the first inmates.

Equestria… it's an idyllic place on the surface, but its history is a rabbit hole. A dark abyss of endless questions and mystery. Just how deep does it go?