Parasite Dimension?

[Grumpy RPG Reviews]

The late and much missed writer Terry Pratchett wrote about "parasite dimensions."

They are not the same thing as alternate timelines or simply a parallel universe. They are usually malevolent, and home to malevolent creatures. Inside the dimension, time does not function. Locals are vulnerable to iron.

But aside from that I wonder how to use the concept in gaming terms. Perhaps, the parasite dimension is connected to the main dimension via a few gates and portals. And maybe in the area around these gates and portals magic is harder to use, people do not heal properly, etc.

How would you handle this, in terms of game mechanics?

 

[Dannyalcatraz]

Sounds kind of like some descriptions of the fey realm of legend...especially the part about the natives’ vulnerability to iron.

In keeping with the parasitic theme, perhaps no true innovation occurs therein. New tech, new magic, all must come from the main dimension. Things would look..archaic.

Taken further, perhaps even biological reproduction is limited in some way. That would be the reason for “changelings”: the young fey gets a chance to grow, the stolen child adds vitality to the withered race of its new parents.

 

[Sunseeker]

So like, "The Dark Dimension" and Dormammu?

I'm assuming you're talking about a dimension which draws energy from nearby dimensions. As opposed to say, a dimension filled with malevolent parasites or something.

I'd say: if you were close to one of these portals or bridges, there'd be a reduction in the functioning of magic and healing (natural and magic) and life wouldn't grow as well, getting worse the closer you get to the portal. The focus of the "Parasite Dimension" is mainly on the energy of non-parasitic universes. It doesn't actively kill living things, it just makes survival more difficult for them.

HOWEVER, if you were to go over to the other side, your magic would work normally. BUT the Parasite Dimension has no natural magical or life regeneration. If you're low on any type of resource, you'll need to take it from someone else, be that another dimension or another being within the Parasite Dimension. The Parasite Dimension itsself won't kill you or even sap your energy once you're in it. The "drain" that the normal dimensions experience is the collective "drain" those within the Parasite Dimension place on the dimensions outside. There'd probably have to be some restoration effect granted when killing an enemy.

Poking through from the normal dimensions to the Parasite Dimension is hard. The other way around is not. Some kind of Will check to make a personal, temporary breach (IE: to reach out and draw in energy for yourself only) and some kind of arcane ritual to set up a permanent gateway, or even a temporary one.

However, the "drain" effect has side-effects. You take on elements of the things you take energy from, mental and physical effects, which is why most beings in the Parasite Dimension are strange chimeric creatures, beings of pure energy, and almost universally insane. When taking in magical energy, a primary Will save of some sort (to avoid or reduce the madness), with a secondary lesser Con save(to avoid or reduce the mutation), when taking in life energy, a primary Con save and a secondary Will save.

You'd definitely need to run some kind of Madness and Corruption/Taint rules.

 

[Eltab]

How would you handle this, in terms of game mechanics?

If you are in the general vicinity of a portal and quaff a healing potion, you must re-roll a maximum roll on the die.
If you are too close to a portal and quaff a healing potion, you must use a die that is half the size (d8 becomes d4, &c).

If you are inside the parasite dimension and quaff a healing potion, you roll as normal but all the monsters in the room heal 1 HP each before you get any.
All the monsters in the parasite dimension can sense Healing Potions, like iron to a magnet. They will act in accordance with their INT, WIS, and alignment, but one goal of their actions is to obtain the Healing Potions for themselves.