A downloadable mod

KEYMASTER is a gameplay mod for GZDoom 3.0 or later that works with almost any Doom or Heretic level.

On every level a random monster is made THE KEYMASTER, tougher and faster than its comrades. Level exits won't work until you've killed THE KEYMASTER and claimed the key. But you can't damage THE KEYMASTER until you find THE ARROW OF SLAYING somewhere in the level. To find it, watch the icon on your HUD and listen for the pulse sound; it'll get quicker as you get closer.

Levels with no monsters, no pickups, or no exit switch/teleporters (eg boss
levels) will give an error and behave normally.

Configuration options are available, see the included readme for details.

CategoryGame mod
Release date May 24, 2017
Rated 5.0 out of 5 stars
(1 total ratings)
AuthorJP LeBreton
TagsDoom, mod
Average sessionA few minutes
InputsKeyboard, Mouse


doom-keymaster-mod.zip 73 kB
Version 2 Apr 05, 2019

Development log


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(1 edit)

Muy buen mod, bastante divertido me gusto. Te hace dar vueltas por todo el nivel, primero buscando la flecha, y luego al tipo que tiene la llave, el cual te lleva a conocer mejor el nivel y descubrir secretos que no conocias.

Are there any updates to this mod in the future?

If so, I have an idea:

What if the goal is to assemble more than 1 parts of the Arrow of Slaying to kill more than 1 Keymasters to collect more master keys needed for a single exit in every map?

Or what if the Keymaster summons keyminions to aid it?

Or what if the item/secret completion reward gives all players 1 Arrow of Slaying?

Can you add compatibilities to MK-Champions, LegenDoom, and other universal gameplay mods for GZDoom?

(1 edit)

I tried to run Keymaster in GZDoom 3.7.2, but I got 2 errors.

The Lines are 75 and 162 in handler.txt.

The result is an error "Invalid Statement".

That's why I can't run Keymaster at all.

Is there any way to fix that?

This is due to a bug in the GZDoom 3.7 series; GZDoom 4.0 was just released and does not exhibit this issue, give that a shot: https://forum.zdoom.org/viewtopic.php?f=1&t=64188