Deep nether
by Tkhy
Deep Nether adds a cold, cruel dimension that lies beneath the Nether, reached through a ruined portal and a hidden portal altar.
What it does
The deeper dimension is modeled on the Nether but colder and harsher. Players who travel into it find terrain that resembles the Nether in layout while differing in its cold environment and dangers. The dimension can be entered from the Nether, and it sits further down than the Nether itself.
Access starts with a ruined portal, which generates only in the Nether and must be activated with a key. Entering the deeper layer through a portal causes that portal to be destroyed immediately, so the way in is one-time and cannot be reused. Getting back to the surface requires finding a portal altar in the deep dimension; right-clicking the altar returns the player to the surface spawn point. The mod is distributed under the MIT License and is not open source. It runs on client and server, so the server and every player need it, and the NeoForge files target 1.21.4 only, with 1.0.0 as the latest file in the alpha channel.
Key features
Cold deeper dimension
A second layer below the Nether with cold, cruel terrain that is similar in layout to the Nether.
Ruined portal access
Ruined portals generate only in the Nether and open the way to the deep dimension when activated with a key.
Altar return
A portal altar in the deep dimension returns the player to the surface spawn point on right-click.
One-way entry
Passing through a portal into the deeper layer destroys that portal, so a player must return by the altar.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Who it’s for: Players who want a colder, harsher dimension beyond the Nether and are prepared for an alpha-stage mod with known bugs. The author recommends backing up the world before use, since the early version contains many bugs.
How it compares
Ruined Portal Only (Neoforge) is open source under the GNU General Public License v3.0 only, is built for NeoForge 1.21 – 1.21.1 and runs on client and server. The Deep Echo is a NeoForge server-side mod for 1.21.1 – 1.21.4 under All rights reserved, so only the server needs it. FrostRealm is open source under the GNU Lesser General Public License v3.0 only, with NeoForge files for 1.21.3 – 1.21.10 that run on client and server.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Deep nether | NeoForge | 1.21.4 | Client and server | 2025-06-03 |
| Ruined Portal Only (Neoforge) | NeoForge | 1.21 – 1.21.1 | Client and server | 2026-04-26 |
| The Deep Echo | NeoForge | 1.21.1 – 1.21.4 | Server-side only | 2025-09-05 |
| FrostRealm | NeoForge | 1.21.3 – 1.21.10 | Client and server | 2025-10-16 |
Questions
Does Deep Nether need a specific loader?
Does a server need Deep Nether installed?
Why does a portal disappear after entering the deep dimension?
Is Deep Nether safe to use on an important world?
In the catalog
Deep nether is one of 8,515 World generation mods on ModsFinder, and one of 4,175 World generation mods for NeoForge. 17,979 mods support Minecraft 1.21.4.
More from Tkhy
Similar mods
What the author says
This mod allows you to travel to a place even deeper than the Nether. Everything there is very similar to the Nether, but unlike it, the environment is very cold and cruel.
Official listing
- Modrinth page
- modrinth.com/mod/deep-nether
- Owner
- Tkhy
- Published
- 2025-06-02
- Updated on Modrinth
- 2025-06-03
- Facts verified
- 2026-10-15