diff --git a/lib/map.js b/lib/map.js
index 886bc31..720bf3e 100755
--- a/lib/map.js
+++ b/lib/map.js
@@ -1163,7 +1163,52 @@ const DUNGEON_ROWS = [
   '#..........................................................#',
   '#..........................~~~~~~...........................#',
   '############################################################'
-].map((row) => row.padEnd(62, '#'))
+// The ruins were drawn a few columns short on the right and every row ended
+// at a different wall column; padEnd used to hide that from defineMap()'s
+// rectangularity check (#10). Normalizing to one fixed width gives the ruins
+// a straight east wall, so the check means something again.
+].map((row) => (row + '###').slice(0, 60) + '#')
+
+/**
+ * The ruins are not empty anymore: three residents camp different chambers,
+ * reusing the exact NPC machinery the city already runs (nearbyNpc header,
+ * e-to-talk, interactNpc dialogue) - issue #10's minimum fix.
+ */
+const DUNGEON_NPCS = [
+  {
+    id: 'eco',
+    name: 'Eco de las ruinas',
+    role: 'vidente',
+    x: 10,
+    y: 7,
+    sprite: NPC_SPRITES.resident,
+    anchorY: NPC_SPRITES.resident.length - 1,
+    color: 'cyan',
+    line: 'los muros recuerdan mas pasos que los vivos'
+  },
+  {
+    id: 'tadeo',
+    name: 'Tadeo',
+    role: 'minero',
+    x: 30,
+    y: 13,
+    sprite: NPC_SPRITES.resident,
+    anchorY: NPC_SPRITES.resident.length - 1,
+    color: 'yellow',
+    line: 'la V fue salida, no entrada: alguien selló el resto'
+  },
+  {
+    id: 'gata',
+    name: 'Gata de las ruinas',
+    role: 'gato',
+    x: 40,
+    y: 17,
+    sprite: NPC_SPRITES.resident,
+    anchorY: NPC_SPRITES.resident.length - 1,
+    color: 'gray',
+    line: 'miau'
+  }
+]
 
 /**
  * Turn art plus metadata into a map, checking the art is rectangular.
@@ -1212,7 +1257,8 @@ const MAPS = {
     name: 'las ruinas bajo el castillo',
     rows: DUNGEON_ROWS,
     spawn: { x: 3, y: 2 },
-    arrive: { x: 3, y: 2 }
+    arrive: { x: 3, y: 2 },
+    npcs: DUNGEON_NPCS
   }),
   coliseum: defineMap({
     id: 'coliseum',
diff --git a/test/dungeon-content.test.js b/test/dungeon-content.test.js
new file mode 100644
index 0000000..2f9cf57
--- /dev/null
+++ b/test/dungeon-content.test.js
@@ -0,0 +1,49 @@
+const { test } = require('brittle')
+const { Runa } = require('../lib/game.js')
+const M = require('../lib/map.js')
+
+function press(game, name) {
+  return game.onKey({ type: 'key', is: (...keys) => keys.includes(name) })
+}
+
+function startGame(game, name = 'Tomas') {
+  press(game, 'enter')
+  for (const ch of String(name)) {
+    game.onKey({ type: 'key', sequence: ch, ctrl: false, meta: false, is: () => false })
+  }
+  press(game, 'enter')
+}
+
+test('the ruins host three residents on walkable ground (#10)', (t) => {
+  const npcs = M.MAPS.dungeon.npcs
+  t.ok(Array.isArray(npcs) && npcs.length >= 3, 'dungeon defines its own residents')
+  for (const n of npcs) {
+    t.ok(!M.isSolid(M.MAPS.dungeon, n.x, n.y), `${n.name} stands on open floor at ${n.x},${n.y}`)
+  }
+})
+
+test('the east wall of the ruins is one straight line now (#10)', (t) => {
+  const city = M.MAPS.dungeon
+  const w = city.width
+  let aligned = true
+  for (let y = 0; y < city.height; y++) {
+    if (city.rows[y].length !== w || city.rows[y][w - 1] !== '#') aligned = false
+    if (!M.isSolid(city, w - 1, y)) aligned = false
+  }
+  t.is(w, 61, 'normalized to a single declared width')
+  t.ok(aligned, 'column 60 is wall on every row - no more jagged mouth')
+})
+
+test('talking inside the ruins reaches a resident instead of void (#10)', (t) => {
+  const game = new Runa({ presence: false })
+  startGame(game)
+
+  const npc = M.MAPS.dungeon.npcs[0]
+  game.walker.placeAt('dungeon', npc.x + 1, npc.y)
+  press(game, 'e')
+
+  t.ok(
+    !game.log.some((line) => String(line).includes('aca no hay nada')),
+    'the resident answers instead of the void'
+  )
+})
\ No newline at end of file
diff --git a/test/index.js b/test/index.js
index 7be3ead..47f34eb 100644
--- a/test/index.js
+++ b/test/index.js
@@ -19,6 +19,7 @@ const {
 const render = require('../lib/render.js')
 
 require('./sage.test.js')
+require('./dungeon-content.test.js')
 
 function press(game, name) {
   return game.onKey({ type: 'key', is: (...keys) => keys.includes(name) })