diff --git a/abms.lua b/abms.lua
index 810c323..a999e49 100644
--- a/abms.lua
+++ b/abms.lua
@@ -12,6 +12,24 @@ minetest.register_globalstep(function(dtime)
 		return
 	end
 
+	local pos
+	for k, v in pairs(minetest.luaentities) do
+		if not v.fortress_check then
+			pos = v.object:getpos()
+			if fun_caves.is_fortress(pos) and v.hp_max and v.object and v.health and v.damage then
+				local factor = 1.5 + (pos.y / -3100)
+				v.hp_max = math.floor(v.hp_max * factor)
+				v.damage = math.floor(v.damage * factor)
+				print("Promoting "..v.name..": "..v.hp_max.." at "..pos.x..","..pos.y..","..pos.z)
+				v.object:set_hp(v.hp_max)
+				v.health = v.hp_max
+				v.fortress_check = true
+				check_for_death(v)
+				--print(dump(v.damage))
+			end
+		end
+	end
+
 	for id, player in pairs(minetest.get_connected_players()) do
 		minp = vector.subtract(player:getpos(), 0.5)
 		maxp = vector.add(player:getpos(), 0.5)
diff --git a/fortress.lua b/fortress.lua
index d525022..da3ab06 100644
--- a/fortress.lua
+++ b/fortress.lua
@@ -9,6 +9,9 @@ fun_caves.fortress = function(node, data, area, minp, maxp, level)
 	local n = 16
 	local walls = {}
 	local a, b, c, i, j, u, v, x, y, z, ivm, set, dox, doz
+	local floor = node('fun_caves:dungeon_floor_1')
+	local outer_wall = node('fun_caves:dungeon_wall_2')
+	local inner_wall = node('fun_caves:dungeon_wall_1')
 
 	for y2 = 0, n-1 do
 	--for y2 = 0, 0 do
@@ -27,12 +30,12 @@ fun_caves.fortress = function(node, data, area, minp, maxp, level)
 						if math.floor((z - minp.z) / 5) == doz and math.floor((x - minp.x) / 5) == dox and (z - minp.z) % 5 ~= 0 and (x - minp.x) % 5 ~= 0 and y ~= minp.y then
 							data[ivm] = node("air")
 						else
-							data[ivm] = node('default:steelblock')
+							data[ivm] = floor
 						end
 					elseif x == minp.x or z == minp.z or x == maxp.x or z == maxp.z then
-						data[ivm] = node('default:steelblock')
+						data[ivm] = outer_wall
 					elseif (z - minp.z) % 5 == 0 or (x - minp.x) % 5 == 0 then
-						data[ivm] = node("default:sandstone")
+						data[ivm] = inner_wall
 					else
 						data[ivm] = node("air")
 					end
diff --git a/goblin_coal.lua b/goblin_coal.lua
index 4c29316..b0ac2f2 100644
--- a/goblin_coal.lua
+++ b/goblin_coal.lua
@@ -121,7 +121,7 @@ mobs:register_mob("fun_caves:goblin_coal", {
 
 })
 mobs:register_egg("fun_caves:goblin_coal", "Goblin Egg (coal)", "default_mossycobble.png", 1)
-mobs:register_spawn("fun_caves:goblin_coal", {"default:coalblock", "default:stone_with_coal"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
+mobs:register_spawn("fun_caves:goblin_coal", {"default:coalblock", "default:stone_with_coal", "group:fortress"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
 mobs:register_spawn("fun_caves:goblin_coal", {"default:mossycobble", "fun_caves:hot_cobble"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
 
 minetest.register_node("fun_caves:stone_with_coal_trap", {
diff --git a/goblin_copper.lua b/goblin_copper.lua
index d9a30e1..0940831 100644
--- a/goblin_copper.lua
+++ b/goblin_copper.lua
@@ -120,7 +120,7 @@ mobs:register_mob("fun_caves:goblin_copper", {
 	end,
 })
 mobs:register_egg("fun_caves:goblin_copper", "Goblin Egg (copper)", "default_mossycobble.png", 1)
-mobs:register_spawn("fun_caves:goblin_copper", {"default:stone_with_copper"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
+mobs:register_spawn("fun_caves:goblin_copper", {"default:stone_with_copper", "group:fortress"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
 mobs:register_spawn("fun_caves:goblin_copper", {"default:mossycobble"}, 100, 0, 1 * fun_caves.goblin_spawn_frequency, 3, 101)
 
 minetest.register_node("fun_caves:stone_with_copper_trap", {
diff --git a/mapgen.lua b/mapgen.lua
index b263742..96a671a 100644
--- a/mapgen.lua
+++ b/mapgen.lua
@@ -1,10 +1,11 @@
-local DEBUG = false
+local DEBUG = true
 
 local cave_noise_1 = {offset = 0, scale = 1, seed = 3901, spread = {x = 40, y = 10, z = 40}, octaves = 3, persist = 1, lacunarity = 2}
 local cave_noise_2 = {offset = 0, scale = 1, seed = -8402, spread = {x = 40, y = 20, z = 40}, octaves = 3, persist = 1, lacunarity = 2}
 local cave_noise_3 = {offset = 15, scale = 10, seed = 3721, spread = {x = 40, y = 40, z = 40}, octaves = 3, persist = 1, lacunarity = 2}
 local seed_noise = {offset = 0, scale = 32768, seed = 5202, spread = {x = 80, y = 80, z = 80}, octaves = 2, persist = 0.4, lacunarity = 2}
 local biome_noise = {offset = 0.0, scale = 1.0, spread = {x = 400, y = 400, z = 400}, seed = 903, octaves = 3, persist = 0.5, lacunarity = 2.0}
+local fortress_noise = {offset = 0, scale = 1, seed = -4082, spread = {x = 200, y = 200, z = 200}, octaves = 2, persist = 1, lacunarity = 2}
 
 
 local node_cache = {}
@@ -103,6 +104,31 @@ end
 --	end
 --end
 
+fun_caves.is_fortress = function(pos)
+	local cs = csize
+	if not cs then
+		-- Fix this to get csize, somehow.
+		cs = {x=80, y=80, z=80}
+	end
+
+	local x = math.floor((pos.x + 33) / cs.x)
+	local y = math.floor((pos.y + 33) / cs.y)
+	local z = math.floor((pos.z + 33) / cs.z)
+
+	if y > -3 or (pos.y + 33) % cs.y > cs.y - 5 then
+		return false
+	end
+
+	local n = minetest.get_perlin(fortress_noise):get3d({x=x, y=y, z=z})
+	n = (n * 10000) % 20
+
+	if n == 1 or DEBUG then
+		return true
+	end
+
+	return false
+end
+
 
 local function generate(p_minp, p_maxp, seed)
 	minp, maxp = p_minp, p_maxp
@@ -121,7 +147,7 @@ local function generate(p_minp, p_maxp, seed)
 	math.randomseed(minetest.get_perlin(seed_noise):get2d({x=minp.x, y=minp.z}))
 
 	local fortress = maxp.y / 3100
-	if maxp.y < -250 and (DEBUG or math.random(20) == 1) then
+	if fun_caves.is_fortress(minp) then
 		fun_caves.fortress(node, data, area, minp, maxp, math.ceil(maxp.y / 3100))
 		write = true
 	else
diff --git a/nodes.lua b/nodes.lua
index 823f7f9..9b142f6 100644
--- a/nodes.lua
+++ b/nodes.lua
@@ -1,6 +1,26 @@
+-- dungeon floor, basic
+local newnode = fun_caves.clone_node("default:stone")
+newnode.description = "Dungeon Stone"
+newnode.legacy_mineral = false
+newnode.groups = {fortress = 1}
+minetest.register_node("fun_caves:dungeon_floor_1", newnode)
+
+-- dungeon walls, basic
+local newnode = fun_caves.clone_node("default:sandstone")
+newnode.description = "Dungeon Stone"
+newnode.groups = {fortress = 1}
+minetest.register_node("fun_caves:dungeon_wall_1", newnode)
+
+-- dungeon walls, type 2
+local newnode = fun_caves.clone_node("default:desert_stone")
+newnode.description = "Dungeon Stone"
+newnode.groups = {fortress = 1}
+minetest.register_node("fun_caves:dungeon_wall_2", newnode)
+
+-- ice -- add cold damage
 minetest.add_group("default:ice", {surface_cold = 3})
 
---thin (transparent) ice
+-- ice, thin -- transparent
 minetest.register_node("fun_caves:thin_ice", {
 	description = "Thin Ice",
 	tiles = {"caverealms_thin_ice.png"},
@@ -15,7 +35,6 @@ minetest.register_node("fun_caves:thin_ice", {
 	paramtype = "light",
 })
 
-
 --minetest.register_node("fun_caves:bright_air", {
 --	drawtype = "glasslike",
 --	tiles = {"technic_light.png"},
diff --git a/sand_monster.lua b/sand_monster.lua
index c58c8dd..e7d7f81 100644
--- a/sand_monster.lua
+++ b/sand_monster.lua
@@ -47,6 +47,6 @@ mobs:register_mob("fun_caves:sand_monster", {
 	},
 })
 
-mobs:register_spawn("fun_caves:sand_monster", {"group:sand"}, 20, 0, 4000, 3, -50)
+mobs:register_spawn("fun_caves:sand_monster", {"default:sand"}, 20, 0, 4000, 3, -50)
 
 mobs:register_egg("fun_caves:sand_monster", "Deep Sand Monster", "default_sand.png", 1)