Corridors of Time

A network of passageways crafted at the dawn of time to connect all places and all times, they were used for years by the modrons to preserve order and ensure that reality was progressing as it should.

The known entrances and most of the accessible areas are still guarded by patrols of Pentadrones and Quadrones, though many of the interior Corridors have since been abandoned and left to ruin. In those abandoned corners lurk bands of travelers lost in time. Since time does not pass in the Corridors, some of these bands have been lost for years or even centuries and many have devolved into madness by their extended isolation.


It is possible to navigate the corridors, primarily by comparing architecture, historical artifacts, and other clues. During a short rest, a character can make a DC 15 History check to determine the approximate time period that the room that they are in borders.

Any time you pass through a doorway within the corridor, the DM should roll on the following chart to determine the time that the room borders on.

d20 Time passed
1 -1d10 x 10 years
2 -1d10 years
3-5 -1d6 months
6-8 -1d6 days
9-12 1d6 days
13-17 1d6 months
18-19 1d10 years
20 1d10 x 10 years

The Corridors of Time are an endless labyrinth. To simulate this, use the rules for Random Dungeons found in Appendix A of the Dungeon Masters guide. Since the rooms exist in different times, rooms and corridors may overlap and exist in space without ever connecting. Use the Planar Gate dungeon chart for determining the purpose of the rooms, with any planar junctions instead being exits from the Corridors. Inhabitants of the dungeon should be determined using the following chart.


Some rooms have permanent exits. However, most rooms simply border on a time period. It is possible to create an exit from the corridors, using a ritual known only to the modrons and a select few other individuals.

Time Scape

5th-level transmutation (ritual)
Casting: 1 minute
Range: Touch
Components: V, S, M (diamond dust worth 10gp, consumed in the casting of this ritual)
Duration: Concentration, up to 1 minute
You draw an hourglass in diamond dust on frame of any doorway. If you are within the Corridors of Time, the door opens into a random door in the time that borders the room you are in. If you are outside of the Corridors of Time, the door opens into the Corridors. Once you stop concentrating, the door slams shut and returns to its normal functionality.

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d20 Monsters
1 Rakshasa
2 Vrock
3 Chain Devil
4 Arcanoloth
5 Mezzoloth
6-7 Githyanki Knight
8-12 1d4 Pentadrones, 1d6 Quadrones, 1d8 Tridrones
13-14 Assassin
15 Assassin
16-18 1d4 Pentadrones, 1d6 Quadrones, 1d8 Tridrones
19 Lich
20 Solar