diff --git a/Source/monster.cpp b/Source/monster.cpp
index 4b637e4cb..3b05d9db7 100644
--- a/Source/monster.cpp
+++ b/Source/monster.cpp
@@ -975,7 +975,7 @@ void PlaceQuestMonsters()
 			UberDiabloMonsterIndex = -1;
 			int i1;
 			for (i1 = 0; i1 < nummtypes; i1++) {
-				if (Monsters[i1].mtype == UniqMonst[12].mtype) // TODO: replace 12 with hellfire unique monster enum when it gets created
+				if (Monsters[i1].mtype == UniqMonst[UMT_NAKRUL].mtype)
 					break;
 			}
 
@@ -988,7 +988,7 @@ void PlaceQuestMonsters()
 				}
 			}
 			if (UberDiabloMonsterIndex == -1)
-				PlaceUniqueMonst(12, 0, 0);
+				PlaceUniqueMonst(UMT_NAKRUL, 0, 0);
 		}
 #endif
 	} else if (setlvlnum == SL_SKELKING) {
diff --git a/enums.h b/enums.h
index 186abfb6a..288d48ac3 100644
--- a/enums.h
+++ b/enums.h
@@ -1805,6 +1805,11 @@ typedef enum {
 	UMT_LACHDAN   = 7,
 	UMT_WARLORD   = 8,
 	UMT_BUTCHER   = 9,
+#ifdef HELLFIRE
+	UMT_HORKDMN   = 10,
+	UMT_DEFILER   = 11,
+	UMT_NAKRUL    = 12,
+#endif
 } _uniq_monsterid;
 
 typedef enum monster_flag {
@@ -2178,6 +2183,10 @@ typedef enum dungeon_type {
 	DTYPE_CATACOMBS = 0x2,
 	DTYPE_CAVES     = 0x3,
 	DTYPE_HELL      = 0x4,
+#ifdef HELLFIRE
+	DTYPE_NEST      = 0x5,
+	DTYPE_CRYPT     = 0x6,
+#endif
 	DTYPE_NONE      = 0xFF,
 } dungeon_type;