Hellmouth Encounter - Brainstorming!

[Wasum]

Hello everybody!

My players are in hell - Avernus - and at the end of last session found a hellmouth that will lead them to the City of Dis where the plot continues. The thing is, I want to make this an interesting (probably non-combat) encounter.

http://fs1.directupload.net/images/180817/636pc5g8.png

This is the respective hellmouth - it is rather small, maybe just big enough to get a large creature inside. The hellmouth will be intelligent, able to speak and give the party a hard time to let them through. I'd appreciate any kind of idea here!

Furthermore this very hellmouth appears not to be guarded which is kinda weird as usually pretty powerful entities claim those landmarks their own. This is why I need a good reason for this very hellmouth to not be guarded OR to actually be guarded but not appering so.

The game takes place on sunday already and I just dont have something good in mind yet.

Therefore: Thank you in advance and let the brainstorming begin!

[PrismCat21]

It isn't evil itself, just a gateway to hell.
The hellmouth got tired of being used as an all access revolving door, and escaped to holy, consecrated land, where the creatures of the lower planes don't care to follow.
The upper planes creatures don't hassle him because having a potential risk free passage to the lower planes comes in handy from time to time.

The hellmouth gives the players a hard time because it enjoys throwing it's reletively recent free-willed weight around. The players provide entertainment for it.

[Lotheb]

If it's intelligent you could stat it up as a creature or an intelligent magic item, and make it it's own guardian. Or just give it the ability to open or close, so it only let's people through if they befriend/impress/convince/bribe (what would a sentient portal value?) It. Maybe to gain passage they have to convince the portal they deserve to go to (EDIT Dis), and to return they have to refute their own successful arguments.

[Wasum]

It isn't evil itself

This really brought up an idea:
The hellmouth is actially an angel, maybe an important one, that died in war against the forces of hell. Ever since then it helps those who opose hell and its ideology to reach their goals. It can disappear at will and switch location all over avernus which is why there is no guarding for it. Now it popped up close to my players to get them to Dis.
But to make it more interesting: It is somehow cursed what makes it a lot more difficult to pass the hellmouth. Do you maybe have an idea how such a curse could look like?

[PrismCat21]

[
But to make it more interesting: It is somehow cursed what makes it a lot more difficult to pass the hellmouth. Do you maybe have an idea how such a curse could look like?
When it died, it had unintentionally absorbed too much feel energy (demonic/devilish/evil/whatever) from the lower planes.
That's why it's tied to it and can grant passage. The curse is because it absorbed so much, it is unable to return to the higher planes.
The more the gateway is used, the stronger it's connection becomes to the lower planes. The stronger the connection, the more corrupted it becomes.

I hope I made sense. Just woke up from little sleep.

[Wasum]

[
When it died, it had unintentionally absorbed too much feel energy (demonic/devilish/evil/whatever) from the lower planes.
That's why it's tied to it and can grant passage. The curse is because it absorbed so much, it is unable to return to the higher planes.
The more the gateway is used, the stronger it's connection becomes to the lower planes. The stronger the connection, the more corrupted it becomes.

I hope I made sense. Just woke up from little sleep.

I like that idea but I‘m not sure about the exact consequences for my party. This seems like a great explaination but how do I make this a challenging and fun encounter?

[Wasum]

As the game takes place tomorrow I‘d really love to see some ideas! :D

[Zaq]

What motivates an intelligent hellmouth? How does it view the world? What does it mean to it for someone to pass through it? What would cause it to view the PCs favorably or unfavorably? Does it like being used as a door, or does it feel degraded and disrespected to be used as a door? Is it interested in keeping things in (or out of) certain layers of Baator, or does it not really care about that?

Can it move? Maybe it’s just lonely and bored. What if it were willing to help just in exchange for some interesting news from somewhere that isn’t the Lower Planes? Or maybe it wants a message from another hellmouth somewhere else (or wants a message taken to said other hellmouth). You could even have the PCs be the go-betweens in a long-distance hellmouth relationship!

[Ripptor]

https://vignette.wikia.nocookie.net/disney/images/9/94/Aladdin-disneyscreencaps.com-372.jpg/revision/latest?cb=20140809202707

I like the idea of a Hellmouth that only opens to send in those that can fend off the forces of Evil. But, in the vein of Aladdin's intelligent Cave of Wonders, perhaps it wants to only send in those that are worthy, AKA can truly help, and doesn't want to send the unprepared to an early grave? This would clear the conscience of the Hellmouth willing sending people to Baator. The Hellmouth is thus unguarded both due to it being Good, and because it guards itself!

The encounter with the Hellmouth would revolve around trying to convince the Hellmouth to open for Good(tm) reasons:

1) Your party are Good(tm) people.
2) Your party is fighting on behalf of a Good(tm) cause.
3) Your party actually needs to travel through to achieve your goals.
4) The Hellmouth won't just be sending your party off the their death on the other side.

That last piece might be the most interesting... If you can't convince it verbally, perhaps it spits out some challenges in order to test the party's ability? The Hellmouth can be used both as a gate and a summons, so (if it feels the need) it could summon forth some CR-appropriate (or slightly higher) encounters to challenge the party, once they've done all the other required convincing.

Alternatively, if the party does try to force the issue, the Hellmouth is probably happy to temporarily summon some nasties in order to kill what is feels like are threats. If they are evil-doers trying to get in, let Evil kill Evil. If they are Good and are prepared to die on the other side, they should either survive the encounter or die on their home plane, rather than in Baator.

So, try to allow them to negotiate. If they cannot, then it becomes a fight, or some other PC cleverness to try and prove their worth. Put on a show, display some value, whatever they can come up with!