What would you guard a gate to the Abyss with?

[Herobizkit]

Sphere of Annhiliation.

Optionally, along the same lines as protecting a gate with another gate to the same place, have some sort of temporal distortion around it so that it only exists at one point in time. Then you'd need some kind of time travel to get at it...

But you know what can of worms that would open up...

 

[Nightfall]

Hero,

Yeah it might bring out the Harbinger of the Age of Worms too.

 

[Lifelike]

Would I be remiss in suggesting hiring a Vampire slayer?

*sheepish pop-culture grin*

 

[Jeremy757]

Build a huge tomb-like dungeon complex. Fill the dungeon with dangerous traps, constructs and undead guardians. The complex should be multi-leveled with heavily locked and barred doors between the levels so that if one level is breached, the invaders have to go through all the challenges and then get through another entrance and start all over again. Leave a few openings in the first level so that local wildlife and demihumans can get in and establish lairs and defenses of their own. Use as much magic as feasible on the lower levels with permanent spells like mentioned above. Make the place a deathtrap.

Take your deathtrap and place it half a mile away from the gate. Surround the gate with a permanent forcecage, surround that with a few feet of adamantine, surround that with lead, then put the whole mess under a pile of solid rock suitable for the terrain. Include some nice nooks and crannies for things like rabbits and birds to take shelter in. Add dirt and grass and whatnot for camoflauge.

Now if you're an adventurer or evil overlord, where are you going to look for the Gate of Unhappy Badness? The huge elaborate dungeon where gobs of danger, experience and possibly treasure awaits? Or that big rock covered in moss where the bunnies live?

I love this idea, but I think the bunnies need to secretly have big pointy teeth and be capable of decapitation. Secretly, of course.

 

[nameless]

I would first build a weapon suitable for use against the Nine Hells. Maybe a set of scrying crystals that watch the Lords of Hell. And I would tie those crystals to an unhallow spell near the gate, so they only function if the unhallow remains active. If unhallow ends, the crystals power down permanently. I'd use the unhallow to keep a permanent Dimensional Lock on the area (the duration is 1 year). This prevents demons from entering in the gate and teleporting around the world.

Then I would put a big mountain right over the gate with no way in or out, no treasure, and no indication that anything important is there. And encase the gate room in a thick layer of lead so no divinations can find it.

Once the gate room is complete, I'd go and find the most powerful demon I could about it. I'd tell him that there is a powerful weapon to use against the Nine Hells in there, but it only works on unhallowed ground, and if the unhallow ever lapses, the weapon is useless. All the demons have to do is keep up the unhallow spell yearly and their weapon will work forever. They can trust me, I'm a paladin.

Then watch as the demons trip over themselves to fortify the gate and make sure the unhallow (and thus dimensional lock) never falls. They will voluntarily keep the gate a non-issue.