Magic portal

^ magic portal
Generates	Never randomly; special levels and branches only
Effect	Transports between branches

A magic portal, ^, is a type of trap that appears in NetHack. When activated, a magic portal takes you to a corresponding square on the destination level, which can be in a different branch of the dungeon altogether.

Generation

Magic portals are never randomly generated, and can be found in very specific areas:

• A magic portal leading to the Quest will occur on a dungeon level from 11 to 16, where it is placed randomly in a normal dungeon room (i.e. with no stairs).
• A magic portal leading to Fort Ludios can appear in a vault anywhere from dungeon level 11 to Medusa.
  • This portal is the only one that is not guaranteed to appear - several factors can influence this possibility, such as the limit of one portal per dungeon level and the fact that vaults are not guaranteed to appear on a compatible floor.
• In Gehennom, a portal in one of the fake Wizard's towers leads to the real one.
• A one-way portal is randomly placed on each of the Elemental Planes, leading to the next.

No more than one magic portal is placed per dungeon level: while it is technically possible for more than one portal to exist on a level, the code does not account for this when transporting you between portal endpoints - it will make use of the first portal it finds in the list of traps, regardless of where you departed from originally.

Description

A magic portal is hidden until it is either activated by you or a monster moving onto its square, or else it is revealed through other means such as a wand of secret door detection. As a trap, a magic portal is not a valid square for teleportation, and unlike other traps it cannot be "escaped": Moving onto a portal's square will always activate it, unless you are placed there as a result of entering the other end of a portal. You can trigger a portal while on its square by using #sit, provided there are no objects on that square.

Pets and monsters that are capable of following you to other levels will follow you through a magic portal if they are adjacent or connected via leash.

A magic portal will not disappear when used unless it is a one-way portal, which are encountered on the Elemental Planes; a one-way magic portal can also be wished for in wizard mode, and stepping on its square causes you to escape the dungeon, ending the game immediately with no option to continue.

While a comment in the source code describes the branchporting effect of the Eye of the Aethiopica as "open[ing] a use-once portal", the effect does not physically create a portal, instead sending the player directly to the target level.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Using a magic portal causes you to be stunned for three turns.

Quest portal

The presence of the magic portal to your quest on a dungeon floor is announced by a message from your quest leader the first time you enter that floor, with an example provided below:

You receive a faint telepathic message from Neferet the Green:
Your help is urgently needed at the Lonely Tower!  Look for a ...ic transporter.
You couldn't quite make out that last message.

Subsequent visits to that floor will print a message like the one shown below until the Quest is completed:

You again sense Neferet the Green pleading for help.

If you attack the quest leader, have converted your alignment, or fail the alignment test more than seven times, the portal will disappear permanently, which can render the game unwinnable.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

The portal will no longer disappear under these circumstances, in order to prevent an unwinnable game.

Removal

While this trap cannot be removed, the portal to your Quest will disappear if you are rejected with prejudice.

Strategy

There are several methods to detect portals before stumbling into them, including the usual methods of trap detection such as reading a scroll of gold detection that is cursed, or else reading a scroll of any beatitude while confused - see the linked article above for details.

Portals and the Amulet

Wearing or wielding the Amulet of Yendor confers a form of magic portal detection that works like a game of "hot and cold": Every game turn, there is a ¹⁄₁₅ chance that you will receive a message about the Amulet glowing, with the heat of its glow indicating your proximity to a magic portal. While this works for any magic portal, it is clearly intended to serve as a means of portal detection while traversing the Planes in the endgame - in practice, and as displayed in the article linked above, there are several far more convenient methods of doing so.

History

Magic portals first appear in NetHack 3.1.0.

Variants

SLASH'EM

In SLASH'EM, the portal to the Quest is found on a dungeon level ranging from 15 to 19, as well as three additional portals to the three alignment quests - the Lawful Quest, Neutral Quest and Chaotic Quest - with one portal per level. Another portal leading to the black market is generated on either dungeon level 22 or 23.

UnNetHack

In UnNetHack, there is also a portal to the magic portal to the black market placed anywhere from dungeon levels 20 to 24.

The portal to Fort Ludios is certain to generate: it will always be in the first eligible vault below level 10, on a floor that does not contain the Quest portal. If no eligible vault is generated, then a guaranteed portal will appear on Medusa's Island.

The Valley of the Dead acts as a hub for several branches tied to Gehennom, with multiple magic portals on the level: one connected to Vlad's Tower that leads directly into the central room of the ground floor; another leading to the Dragon Caves; and a third that leads to Sheol. This hub of portals was made possible using a relatively simple fix.

dNetHack

In dNetHack, magic portals occur in various areas.

The portal to each of the alignment quests are anywhere from dungeon levels 12 to 20. Of note is that each level that contains a portal to one of the quests has a corresponding set layout - in the case of the Chaos Quests, there are three different possible level maps that will appear in a given game, and each correlate to a specific Chaos Quest.

The November NetHack Tournament

In The November NetHack Tournament, the deathmatch arena is a new branch accessible via magic portal on the level immediately above Medusa's Island.

notdNetHack

In notdNetHack, instead of a stair to the Gnomish Mines, the travelling wizard in the village on dungeon level 4 grants you access to the various adventure branches, with a magic portal to the chosen branch replacing the village's fountain - each adventure branch has its own version of Minetown and the entrance to the Windowless Tower to match the theme.

EvilHack

In EvilHack, a magic portal to Goblin Town appears on dungeon level 2 or 3, and another magic portal the Ice Queen's Realm is always generated on the floor above Medusa's Island. Still another magic portal located in the Valley of the Dead leads to a single-level branch known as the Hidden Dungeon; a magic portal on the dungeon level below the Valley leads to Vecna's Domain. The magic portal to Fort Ludios is placed in the first available vault below level 10, similar to UnNetHack.

Infidels start the game with the real Amulet of Yendor in their possession, allowing them to use it at a form of portal detection.

Encyclopedia entry

Portals can be Mirrors, Pictures, Standing Stones, Stone
Circles, Windows, and special gates set up for the purpose.
You will travel through them both to distant parts of the
continent and to and from our own world. The precise manner
of their working is a Management secret.

[ The Tough Guide to Fantasyland, by Diana Wynne Jones ]