diff --git a/src/ascension.lua b/src/ascension.lua
new file mode 100644
index 0000000..9c4d2b4
--- /dev/null
+++ b/src/ascension.lua
@@ -0,0 +1,136 @@
+-- Optional run-wide difficulty mutators a player opts into before a run
+-- starts, in exchange for extra renown once it ends: risk taken on purpose,
+-- unlike events.lua's mutators which fire and fade on their own mid-run
+-- regardless of anyone's choice. A mutator unlocks once meta.lua's own
+-- cross-run tallies (best depth, wins) cross its fixed requirement -
+-- computed live off those tallies rather than persisted, since both only
+-- ever climb, so nothing here needs its own entry in meta.lua's save shape.
+--
+-- Active mutators for the run in progress live on game.ascension, a plain
+-- array of keys in catalog order (see Ascension.resolve), exactly the shape
+-- warren.lua's --mutators flag builds. Plain data, so it serializes with no
+-- special save-format handling, and every combat/essence/sight hook that
+-- reads it (Game:monsterDamageMultiplier, Game:essenceMultiplier,
+-- Game:effectiveRadius) stays a pure function of that array alongside
+-- whatever level-scoped event Events.lua itself is contributing.
+
+local Ascension = {}
+
+Ascension.MUTATORS = {
+  { key = "bloodbound", name = "Bloodbound", desc = "monsters hit 50% harder",
+    renownBonus = 15, requiresDepth = 3, requiresWins = 0, damageMultiplier = 1.5 },
+  { key = "famine", name = "Famine", desc = "essence income halved",
+    renownBonus = 10, requiresDepth = 2, requiresWins = 0, essenceMultiplier = 0.5 },
+  { key = "nightblind", name = "Nightblind", desc = "sight radius reduced by 2",
+    renownBonus = 10, requiresDepth = 2, requiresWins = 0, sightPenalty = 2 },
+  { key = "frail", name = "Frail", desc = "defense halved",
+    renownBonus = 12, requiresDepth = 4, requiresWins = 0,
+    applyToPlayer = function(player)
+      player.baseDefense = player.baseDefense // 2
+      player.defense = player.defense // 2
+    end },
+  { key = "glasscannon", name = "Glass Cannon", desc = "max hp halved, attack doubled",
+    renownBonus = 20, requiresDepth = 0, requiresWins = 1,
+    applyToPlayer = function(player)
+      player.maxHp = math.max(1, player.maxHp // 2)
+      player.hp = math.min(player.hp, player.maxHp)
+      player.baseAttack = player.baseAttack * 2
+      player.attack = player.attack * 2
+    end },
+}
+
+Ascension.byKey = {}
+Ascension.order = {}
+for _, def in ipairs(Ascension.MUTATORS) do
+  Ascension.byKey[def.key] = def
+  Ascension.order[#Ascension.order + 1] = def.key
+end
+
+-- A meta-less caller (no --meta flag at all) can still activate whatever
+-- costs nothing to unlock; every other mutator needs a persistent meta file
+-- to have already banked the depth or win it requires.
+function Ascension.isUnlocked(meta, key)
+  local def = Ascension.byKey[key]
+  if not def then return false end
+  if not meta then return def.requiresDepth == 0 and def.requiresWins == 0 end
+  return meta.bestDepth >= def.requiresDepth and meta.wins >= def.requiresWins
+end
+
+-- Validates a requested list of mutator keys against both the catalog and
+-- `meta`'s own unlock state, returned de-duplicated in catalog order rather
+-- than whatever order the caller supplied - so two runs activating the same
+-- set always see it identically regardless of how --mutators listed them.
+-- An unknown or still-locked key is silently dropped rather than failing
+-- the whole run over one bad flag.
+function Ascension.resolve(meta, requested)
+  if not requested or #requested == 0 then return {} end
+  local wanted = {}
+  for _, key in ipairs(requested) do wanted[key] = true end
+  local active = {}
+  for _, key in ipairs(Ascension.order) do
+    if wanted[key] and Ascension.isUnlocked(meta, key) then
+      active[#active + 1] = key
+    end
+  end
+  return active
+end
+
+function Ascension.isActive(active, key)
+  for _, k in ipairs(active or {}) do
+    if k == key then return true end
+  end
+  return false
+end
+
+function Ascension.damageMultiplier(active)
+  local mult = 1
+  for _, key in ipairs(active or {}) do
+    local def = Ascension.byKey[key]
+    if def and def.damageMultiplier then mult = mult * def.damageMultiplier end
+  end
+  return mult
+end
+
+function Ascension.essenceMultiplier(active)
+  local mult = 1
+  for _, key in ipairs(active or {}) do
+    local def = Ascension.byKey[key]
+    if def and def.essenceMultiplier then mult = mult * def.essenceMultiplier end
+  end
+  return mult
+end
+
+function Ascension.sightPenalty(active)
+  local penalty = 0
+  for _, key in ipairs(active or {}) do
+    local def = Ascension.byKey[key]
+    if def and def.sightPenalty then penalty = penalty + def.sightPenalty end
+  end
+  return penalty
+end
+
+-- Renown bonus percentage this active set adds on top of Meta.renownFor's
+-- own base score, summed rather than compounded - three 15% mutators add
+-- 45%, not a runaway 1.15^3 - so stacking more of them is always a
+-- straightforward trade of more risk for more reward.
+function Ascension.renownBonusPercent(active)
+  local percent = 0
+  for _, key in ipairs(active or {}) do
+    local def = Ascension.byKey[key]
+    if def then percent = percent + def.renownBonus end
+  end
+  return percent
+end
+
+-- Applies every active mutator's one-time player-stat delta, in catalog
+-- order. Meant to run once in Game.new, after Meta.applyAll's perks and any
+-- class delta, since a mutator is the final, voluntary layer of difficulty
+-- stacked on top of whatever build the player already chose.
+function Ascension.applyToPlayer(active, player)
+  for _, key in ipairs(active or {}) do
+    local def = Ascension.byKey[key]
+    if def and def.applyToPlayer then def.applyToPlayer(player) end
+  end
+end
+
+return Ascension
diff --git a/src/atmosphere.lua b/src/atmosphere.lua
new file mode 100644
index 0000000..462c238
--- /dev/null
+++ b/src/atmosphere.lua
@@ -0,0 +1,49 @@
+-- Floor-wide weather: a single condition drawn once at generation (like
+-- `dark`) that colors the whole level rather than one cell of it. Unlike
+-- terrain.lua's per-tile hazards (lava, chasm, ice), a floor's weather has no
+-- position of its own - every numeric hook below is a flat, floor-lifetime
+-- modifier the caller applies once per turn or once at generation, never
+-- something a player can step in or out of.
+
+local Atmosphere = {}
+
+Atmosphere.FOGGY = "foggy"
+Atmosphere.CONSECRATED = "consecrated"
+Atmosphere.INFESTED = "infested"
+
+-- Fixed order so a given rng draw always names the same condition.
+Atmosphere.order = { Atmosphere.FOGGY, Atmosphere.CONSECRATED, Atmosphere.INFESTED }
+
+-- A thick, clinging fog: everyone's sight radius shrinks, monsters and traps
+-- included, before the darkness/torch radius in Game:effectiveRadius is
+-- even considered.
+function Atmosphere.sightPenalty(weather)
+  if weather == Atmosphere.FOGGY then return 2 end
+  return 0
+end
+
+-- Consecrated ground mends the living each turn they linger on it, exactly
+-- like an artifact's fixed regen (see artifacts.ringRegen) but floor-wide
+-- and free of any equipment.
+function Atmosphere.regenBonus(weather)
+  if weather == Atmosphere.CONSECRATED then return 1 end
+  return 0
+end
+
+-- An infested floor's monsters hit harder from the moment they are placed -
+-- a flat, permanent bump baked into their stats at generation time (see
+-- builder.lua), the same way an elite affix or a boss's own catalog entry
+-- already sets a monster's power once and for all.
+function Atmosphere.monsterAttackBonus(weather)
+  if weather == Atmosphere.INFESTED then return 2 end
+  return 0
+end
+
+function Atmosphere.describe(weather)
+  if weather == Atmosphere.FOGGY then return "a thick fog blankets this floor" end
+  if weather == Atmosphere.CONSECRATED then return "this floor is consecrated ground" end
+  if weather == Atmosphere.INFESTED then return "this floor teems with infestation" end
+  return nil
+end
+
+return Atmosphere