Heretic keys

All three Heretic keys: yellow, green and blue

The yellow key is shown on the automap.

The Heretic keys are the three color-coded key objects found in Heretic which allow the player's progress through the game's levels to be controlled. While Heretic's keys are more similar to Doom's in their behavior than to the Hexen keys, there are still a few differences:

• there is only one type for each key color, as opposed to Doom's system of like-colored key cards and skull keys;
• the colors are yellow, green and blue instead of yellow, red and blue;
• vanilla levels are always designed so that keys are obtained in the order yellow, then green, then blue. This convention is not necessarily respected by mods;
• on the easiest skill level, keys appear on the automap;
• locked doors are drawn with their key color on the automap;
• almost all levels are consciously designed to use permanently opening door types for locked doors. This has a significant positive impact on cooperative multiplayer, ensuring that players who die do not need to pick up every key in the map again to keep playing.

Data

The automap color corresponds to the PLAYPAL palette index used to draw locked doors and, if appropriate, keys themselves in the automap. For convenience, the RGB value for that index in the first palette is also provided.

Key data
	Yellow key	Green key	Blue key
Thing type	80 (decimal), 50 (hex)	73 (decimal), 49 (hex)	79 (decimal), 4F (hex)
Enum	MT_CKEY (145)	MT_AKYY (143)	MT_BKYY (144)
Radius	20
Height	16
Sprite	CKYY	AKYY	BKYY
Frames	9 [ABCDEFGHI]	10 [ABCDEFGHIJ]	10 [ABCDEFGHIJ]
Class	Key Pickup
Flags	33554433 (decimal) 02000001 (hex)
Flags list	0: Can be picked up 25: Not in deathmatch
Flags2	0 (decimal) 00000000 (hex)
Automap color	144 (#FFFF00)	220 (#5BBF4F)	197 (#2028C8)

Appearance statistics

The IWAD contains the following numbers of keys:

Episode	Yellow keys	Green keys	Blue keys
City of the Damned	8	7	4
Hell's Maw	8	8	6
The Dome of D'Sparil	8	8	5
The Ossuary	8	6	5
The Stagnant Demesne	8	8	7
Fate's Path	0	0	0

Key gizmos

Green door with two gizmos in E1M9: The Graveyard

Unlike in Doom where special textures are used on door jambs to indicate the color of key needed to open that door, Heretic relies on special objects internally referred to as "key gizmos."

In game, these appear as carved stone statues in the form of a winged and horned creature with a coiled serpent tail, similar in design to the Ssair dragons from Shadowcaster, which each hold up an orb of the same color as the respective key needed to open the door.

Most locked doors are flanked by two such statues, though they occasionally occur alone or not at all.

Gallery

• 

  A key may be placed in a notable location or be decorated to indicate its importance. In E5M5: Hydratyr, the yellow key can be found in the center of a fort.

• 

  Keys may be fiercely guarded. In E3M7: The Chasm, a maulotaur lurks ready to prevent the player from obtaining the green key.

• 

  Although a key can be found quickly, it may take a while before it can be picked up. In E2M3: The River of Fire, the blue key sits on a ledge that requires a switch to lower.

Trivia

• In the manual, the yellow key is called gold.
• The sprites for all three keys vary in size: yellow is the tallest (24x32 pixels), blue is the widest (26x25 pixels), green is the middle (19x25 pixels).
• Each of the keys has a set of sprites to create an animation of its rotation. For some unknown reason, the yellow key only has nine frames of animation, while the green and blue keys have ten frames each.