OLH Companion
by MrElectrooo
OLH Companion is a Fabric client-side validator that a player runs before joining the Last Hell hardcore server, and it is required to join that server.
What it does
When a player clicks Join Server, OLH Companion starts a handshake with the Last Hell network, which checks that the setup matches what the server expects. Players who want to connect need it installed on the client, and the mod does not change anything on the server side.
The validator scans the active mod list and evaluates the result before the player enters the world. It runs its checks in quick validation cycles, and the mod works on its own, with no external API libraries or asset packs needed. Files are released under All rights reserved, so the code is not open source.
The mod is built for Fabric loader on Minecraft 1.21.11 only, and the latest Fabric file, 1.0.0, was published on 2026-06-13. It belongs to the Social category and is listed under Management and Utility as well.
Key features
Handshake with the server
A secure handshake runs when the player selects Join Server, so the network can confirm the client before the connection completes.
Modpack scan
The validator reads the list of active mods and checks it against the rules set for the hardcore server.
Result evaluation
After the scan, the mod evaluates the outcome and lets the player continue into the world when the setup passes.
Specialized hardcore utility
The tool is limited to joining Last Hell, so it does not add gameplay content or change how single-player worlds run.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Joining Last Hell
Players who want to enter the Last Hell hardcore server install the mod so the handshake and scan run on each connection.
Checking a modpack before login
Players using a custom modpack can rely on the scan to confirm their active mods before they try to join.
Who it’s for: Players who plan to join the Last Hell hardcore server on Minecraft 1.21.11 with Fabric. Server owners of other servers have no reason to use it.
How it compares
Server Rules is open source under the GNU Affero General Public License v3.0 or later, runs on client and server and targets Fabric 1.20.1. Multiplayer Hardcore is open source under the MIT License, is server-side only and targets Fabric 1.21, so players join without installing anything. OLH Companion is not open source, is client-side only and targets Fabric 1.21.11 alone.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| OLH Companion | Fabric | 1.21.11 | Client-side only | 2026-06-13 |
| Server Rules | Fabric | 1.20.1 | Client and server | 2025-07-18 |
| Multiplayer Hardcore | Fabric | 1.21 | Server-side only | 2024-07-23 |
Questions
Does OLH Companion need to be installed on the server?
Which Minecraft version does OLH Companion support?
Does OLH Companion require any other mods?
In the catalog
OLH Companion is one of 5,392 Social mods on ModsFinder, and one of 4,084 Social mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
Our Last Hell - Client Validator is a mandatory, highly specialized security utility designed exclusively for the Our Last Hell official Minecraft hardcore server. Built on the Fabric loader for version 1.21.11, its core purpose is to ensure absolute competitive integrity, fair play, and an uncompromised survival…
Official listing
- Modrinth page
- modrinth.com/mod/olh-companion
- Owner
- MrElectrooo
- Published
- 2026-06-13
- Updated on Modrinth
- 2026-06-13
- Facts verified
- 2026-10-15