Author: TimFReilly Current version: Milestone 4 Last change: 2020-09-05 07:07:41 Stage: Design

The Curious Reemergence of Castmire

Castmire is a Custom Magic: the Gathering set and setting developed by the Beacon of Creation podcast community. The plane of Castmire is entirely contained in one colossal mansion. This mansion was, until recently, a hub between the planes of the Multiverse. This has filled the mansion with a menagerie of oddities and ecosystems. Its owner, Barstoe, was once a gracious host and trader with the multiverse. At some point, however, he lost control of both the mansion and his faculties. This plane, all but forgotten to the multiverse for decades, is only now being rediscovered by post-Mending Planeswalkers.

The tone of the plane is "spooky noir" meets "Beauty and the Beast animated furniture" meets "Dungeons & Dragons sprawl". As a set designed with the community, its influences will come from many different people. The conceit of the plane embraces this, encouraging a zoo of creatures and a hoard of items from across the many planes of Magic.

Playing with Castmire

Our newest release for Castmire is Milestone 3, which has:

  • 13 Rares
  • 32 Uncommons
  • 66 Commons

Our goal with Milestone 3 is to test the new mechanics, Inhabit and Jumpscare. Additionally we're looking into the possible color pair themes to the set, which will be the goal for Milestone 4.

We mainly coordinate playtests through Beacon of Creation's Discord:


Castmire has four named mechanics.

Visit {cost} (Play this card face down as a land named Unopened Door with "T: Add C." You may turn this card face up by tapping an untapped creature you control and paying this card's visit cost. Visit as a sorcery.)

  • The collapse of the planar portals of Castmire had the side effect of contaminating many of its rooms with the ecosystems of other planes.
  • Explorers of Castmire won't know whether a beautiful Selesyan garden or Atarka's feeding hall will appear behind the next door.
  • All Colors, with "cares about Visit" showing up in Green so far
  • Visit has been very popular so far and is quite promising.
  • While the "untapped creature" and "sorcery speed" parts of Visit are brought up as too complicated, we've seen their use in playtesting. Removing or changing these requirements are on the table, but we haven't locked into anything.

Inhabit ([cost] ([cost]: Exile this card from your graveyard inhabiting target artifact or creature you control as a sorcery. Inhabited permanent gains this card’s abilities.))

  • Castmire is a collapsing artificial plane, in the process of becoming an Entity (as explored in Children of the Nameless novella). It was "programmed" to seek out guests from across the planes, inviting them in one by one and accommodating their needs, but since the Mending you can check out any time you like but you can never leave.
  • Now its gathered memories and the accumulated spiritual residue of past inhabitants result in items taking on life, occasionally helpful to the survivors but increasingly dangerous and unpredictable.
  • Inhabit cards can create crazy combos by stapling new abilities on cards. Inhabit designs focus on quirky abilities.

Jumpscare (As long as a creature is attacking you alone, you may cast this spell for its jumpscare cost rather than its mana cost and as though it had flash.)

  • A variety of creatures lurk the halls and rooms of Castmire. Between the castaways from other planes and the overloaded magic seeping into the furniture and furnishings, you never know what you'll encounter next.
  • Jumpscare is an attempt at a spooky, goofy mechanic to replace some earlier attempts. The window for the flash mode can be narrow, but we hope to find enough good designs to make it work.

Investigate (Create a Clue artifact token with "2, Sacrifice this artifact: Draw a card.")

  • Oddities and curiosities abound in Castmire. Can they be touched, broken, and turned into something useful?
  • This mechanic is currently the same as it was in Shadows over Innistrad, with the addition of Eldraine-style Clue cards go to along with the tokens.

Setting and Flavor

Haunted Mansion

Castmire was once a bustling plane, serving as a waypoint and trading post for interplanar travel. With the Great Mending, approximately 60 years ago, the plane's portals were severed and the mansion cut off from the multiverse. Those who thought they would only visit the mansion found themselves cut off from their home plane. The state of the mansion initially degraded into chaos, and many of the visitors died or wandered into the endless hallways. In the decades since, though, a peculiar equilibrium has emerged, with some groups settling in and even raising children. Some refuse to settle and instead search for the fabled Exit that will let them go home.

Animated Furniture and Furnishings

The mansion-plane of Castmire is infused with living magic, allowing it to reconstruct and expand itself. Along with that comes a living crew of chairs, tables, rugs, and more. At one time or another, every fixture and fitting has been known to show signs of life, from sconces to tablecloths to loose floorboards. There's speculation as to what intelligence guides these creatures, as they are often seen working together to help clean and repair the rooms.

A Menagerie of Monsters

Even before Castmire was shut off from the rest of the planes, it was known for its zoos of exotic creatures. With the wardens of these places missing or dead, those creatures have been found roaming the rooms. This ecosystem has been further developed by the trapped travelers on Castmire, who have taken to raising and farming creatures from across these planes. The magic of the mansion seems to abide, and entire wings of the building have been transformed to more closely match the planes from which these fauna and flora originate.

Milestone 3

Date: 2020-07-04 03:35:33

Change log:

Milestone 3 Draft

Date: 2020-07-03 06:59:44

Change log:

CC 39 to 43 DC 39 40

Date: 2020-06-28 01:49:53

Change log:


Date: 2020-06-19 07:08:40

CC 34 to 38

Date: 2020-06-12 02:52:15

CC 29 to 33

Date: 2020-05-24 04:08:45

Milestone 2

Date: 2020-04-25 07:20:14

Includes DC33, and CC25-28

Change log:

DC 31 32 CC 23 24

Date: 2020-04-20 05:36:22

M1 Balance 1

Date: 2020-04-12 01:29:42

M1 Flavor

Date: 2020-04-09 05:44:03

Milestone 1

Date: 2020-03-28 05:19:38

CC 19 20

Date: 2020-03-25 18:01:15

DC 25 26

Date: 2020-03-21 23:51:49

Change log:

CC 17 18

Date: 2020-03-17 07:21:15

Change log:

DC 23 24 CC 16

Date: 2020-03-14 21:13:44

Change log:

CC 14 15

Date: 2020-03-10 05:54:25

DC 21 22

Date: 2020-03-08 06:33:48

Change log:

CC 11 12 13

Date: 2020-03-06 04:11:49

Change log:

DC 19 20

Date: 2020-03-02 06:22:54

Change log:


Date: 2020-02-25 06:58:45

Change log:


Date: 2020-02-17 18:39:04

Change log:


Date: 2020-02-11 04:26:07


Date: 2020-02-07 03:58:28


Date: 2020-01-27 06:29:48


Date: 2020-01-14 02:27:37

Change log:

DC 678

Date: 2020-01-07 07:16:22

Change log:


Date: 2019-12-23 06:32:39

Change log:


Date: 2019-12-17 03:37:18

This is the first version of Castmire published on