Special Rooms: Portals to Another Plane

An entry in an ongoing project to generate "special" rooms

This section details the possible functioning of a portal to another plane, but attempts to be agnostic as to what the plane might be, and defers to other texts for the detailing of the physical portal itself.

2A: Can the other side of the portal be perceived without entering?

d2	Nature of Portal
1	No
2	Yes, by looking through the aperture

2B: What does the portal connect to?

The implication of the portal not connecting to anything should be clear: it is effectively one-way. This should be hinted at if the other side of the portal can be perceived.

d20	Portal Connects to...
1-8	Nothing, the portal drops entrants off in open terrain in the target plane
9-19	Another portal, roll to determine it's nature
20	A dedicated portal facility, see Section 2C

2C: Portal facilities

Such facilities are purpose built to provide transport throughout the planes.

d20	Number of Portals in Facility
1-9	1d4+1
10-14	1d6+2
15-18	1d10+4
19-20	1d20+6

2D: How is the portal activated?

d20	The portal is activated...
1-4	By entering it, no special action is otherwise required
5-7	With a key of some sort, which must be (1-2) presented at some sort of device in the same chamber, (3-4) be on the person of an entrant into the portal, (5) be on the person of each entrant (multiple copies of the key are required), or (6) be presented elsewhere in the dungeon.
8-11	With ritual magic, which is either (1-4) described in the same chamber, or (5-6) must be discovered elsewhere.
12-15	With a non-magical ritual which is either (1-4) described in the same chamber, or (5-6) must be discovered elsewhere.
16-19	Only at a certain time each day
20	Only on a certain day each year

2E: Other considerations

For tables detailing the physical characteristics of portals and their keys, see Kefitzah Hederach: Incunabulum of the Uncanny Gates and Portals. Consider that the portal might be hidden or trapped. Table IIIc from Tricks, Empty Rooms, & Basic Trap Design by Courtney Campbell might be useful here.