diff --git a/ADG5.cpp b/ADG5.cpp
index 555cb47..3149c62 100644
--- a/ADG5.cpp
+++ b/ADG5.cpp
@@ -15,8 +15,6 @@ int main(int argc, char **argv)
     auto console = tcod::Console(80, 50);
     auto params = TCOD_ContextParams{};
 
-	int playerx = 40, playery = 25;
-
     params.console = console.get();
 	params.window_title = "Andrew's Dungeon Game 5";
 	params.sdl_window_flags = SDL_WINDOW_RESIZABLE;
@@ -25,7 +23,7 @@ int main(int argc, char **argv)
 	params.argv = argv;
 
     auto context = tcod::Context(params);
-	engine = new Engine(&context, &console);
+	engine = new Engine(80, 50, &context, &console);
 	engine->init();
 
 	while (engine->update()) {
diff --git a/Actor.cpp b/Actor.cpp
index 4e503b1..005826e 100644
--- a/Actor.cpp
+++ b/Actor.cpp
@@ -1,10 +1,23 @@
+#include <cstdio>
 #include "libtcod.hpp"
 #include "Actor.h"
+#include "Map.h"
+#include "Engine.h"
+#include "Ai.h"
+#include "Destructible.h"
+#include "Attacker.h"
 
-Actor::Actor(int x, int y, std::string_view ch, const TCOD_ColorRGB& col) :
-    x(x), y(y), ch(ch), col(col) {
+Actor::Actor(int x, int y, std::string_view ch, std::string name, const TCOD_ColorRGB& col) :
+    x(x), y(y), ch(ch), col(col), name(name),
+    blocks(true),attacker(nullptr), destructible(nullptr), ai(nullptr) {
 }
 
 void Actor::render(TCOD_Console& cons) const {
 	tcod::print(cons, { x, y }, ch, col, std::nullopt);
+}
+
+void Actor::update() {
+	if (ai) {
+		ai->update(this);
+	}
 }
\ No newline at end of file
diff --git a/Actor.h b/Actor.h
index dbb61c1..cfa79ef 100644
--- a/Actor.h
+++ b/Actor.h
@@ -2,12 +2,22 @@
 
 #include "libtcod.hpp"
 
+class Attacker;
+class Destructible;
+class Ai;
+
 class Actor {
 public:
     int x, y; // position on map
     std::string_view ch; // ascii code
     TCOD_ColorRGB col; // color
+    std::string name;
+    bool blocks;
+    Attacker* attacker;
+	Destructible* destructible;
+    Ai* ai;
 
-    Actor(int x, int y, std::string_view ch, const TCOD_ColorRGB& col);
+    Actor(int x, int y, std::string_view ch, std::string name, const TCOD_ColorRGB& col);
     void render(TCOD_Console& cons) const;
+    void update();
 };
\ No newline at end of file
diff --git a/Ai.cpp b/Ai.cpp
new file mode 100644
index 0000000..2e0d1ef
--- /dev/null
+++ b/Ai.cpp
@@ -0,0 +1,129 @@
+#include <SDL3/SDL.h>
+#include "Ai.h"
+#include "Actor.h"
+#include "Engine.h"
+#include "Map.h"
+#include "Destructible.h"
+#include "Attacker.h"
+
+void PlayerAi::update(Actor* owner) {
+	SDL_Event event;
+	int dx = 0, dy = 0;
+
+	if (owner->destructible && owner->destructible->isDead()) {
+		while (SDL_PollEvent(&event)) {
+			switch (event.type) {
+			case SDL_EVENT_QUIT:
+				engine->gameStatus = Engine::QUIT;
+				break;
+			default:
+				break;
+			}
+		}
+		return;
+	}
+	while (SDL_PollEvent(&event)) {
+		engine->context->convert_event_coordinates(event);
+		switch (event.type) {
+		case SDL_EVENT_KEY_DOWN:
+			switch (event.key.key) {
+			case SDLK_UP:
+				dy = -1;
+				break;
+			case SDLK_DOWN:
+				dy = 1;
+				break;
+			case SDLK_LEFT:
+				dx = -1;
+				break;
+			case SDLK_RIGHT:
+				dx = 1;
+				break;
+			default:
+				break;
+			}
+			break;
+		case SDL_EVENT_QUIT:
+			engine->gameStatus = Engine::QUIT;
+			break;
+		default:
+			break;
+		}
+
+		if (dx != 0 || dy != 0) {
+			engine->gameStatus = Engine::NEW_TURN;
+			if (moveOrAttack(owner, owner->x + dx, owner->y + dy)) {
+				engine->map->computeFov();
+			}
+		}
+	}
+}
+
+bool PlayerAi::moveOrAttack(Actor* owner, int targetx, int targety) {
+	if (engine->map->isWall(targetx, targety)) return false;
+	// look for living actors to attack
+	for (Actor** iterator = engine->actors.begin();
+		iterator != engine->actors.end(); iterator++) {
+		Actor* actor = *iterator;
+		if (actor->destructible && !actor->destructible->isDead()
+			&& actor->x == targetx && actor->y == targety) {
+			owner->attacker->attack(owner, actor);
+			return false;
+		}
+	}
+	for (Actor** iterator = engine->actors.begin();
+		iterator != engine->actors.end(); iterator++) {
+		Actor* actor = *iterator;
+		if (actor->destructible && actor->destructible->isDead()
+			&& actor->x == targetx && actor->y == targety) {
+			printf("There's a %s here\n", actor->name.c_str());
+		}
+	}
+	owner->x = targetx;
+	owner->y = targety;
+	return true;
+}
+
+static const int TRACKING_TURNS = 3;
+
+void MonsterAi::update(Actor* owner) {
+	if (owner->destructible && owner->destructible->isDead()) {
+		return;
+	}
+	if (engine->map->isInFov(owner->x, owner->y)) {
+		// we can see the player. move towards him
+		moveCount = TRACKING_TURNS;
+	}
+	else {
+		moveCount--;
+	}
+	if (moveCount > 0) {
+		// we can see the player. move towards him
+		moveOrAttack(owner, engine->player->x, engine->player->y);
+	}
+}
+
+void MonsterAi::moveOrAttack(Actor* owner, int targetx, int targety) {
+	int dx = targetx - owner->x;
+	int dy = targety - owner->y;
+	int stepdx = (dx > 0 ? 1 : -1);
+	int stepdy = (dy > 0 ? 1 : -1);
+	float distance = sqrtf((float)dx * (float)dx + (float)dy * (float)dy);
+	if (distance >= 2) {
+		dx = (int)(round(dx / distance));
+		dy = (int)(round(dy / distance));
+		if (engine->map->canWalk(owner->x + dx, owner->y + dy)) {
+			owner->x += dx;
+			owner->y += dy;
+		}
+		else if (engine->map->canWalk(owner->x + stepdx, owner->y)) {
+			owner->x += stepdx;
+		}
+		else if (engine->map->canWalk(owner->x, owner->y + stepdy)) {
+			owner->y += stepdy;
+		}
+	}
+	else if (owner->attacker) {
+		owner->attacker->attack(owner, engine->player);
+	}
+}
\ No newline at end of file
diff --git a/Ai.h b/Ai.h
new file mode 100644
index 0000000..5a9dba8
--- /dev/null
+++ b/Ai.h
@@ -0,0 +1,25 @@
+#pragma once
+
+class Actor;
+
+class Ai {
+public:
+    virtual void update(Actor* owner) = 0;
+};
+
+class PlayerAi : public Ai {
+public:
+    void update(Actor* owner);
+
+protected:
+    bool moveOrAttack(Actor* owner, int targetx, int targety);
+};
+
+class MonsterAi : public Ai {
+public:
+    void update(Actor* owner);
+
+protected:
+    int moveCount;
+    void moveOrAttack(Actor* owner, int targetx, int targety);
+};
\ No newline at end of file
diff --git a/Attacker.cpp b/Attacker.cpp
new file mode 100644
index 0000000..41fff0a
--- /dev/null
+++ b/Attacker.cpp
@@ -0,0 +1,22 @@
+#include "Attacker.h"
+#include "Actor.h"
+#include "Destructible.h"
+
+Attacker::Attacker(float power) : power(power) {
+}
+
+void Attacker::attack(Actor* owner, Actor* target) {
+    if (target->destructible && !target->destructible->isDead()) {
+        if (power - target->destructible->defense > 0) {
+            printf("%s attacks %s for %g hit points.\n", owner->name.c_str(), target->name.c_str(),
+                power - target->destructible->defense);
+        }
+        else {
+            printf("%s attacks %s but it has no effect!\n", owner->name.c_str(), target->name.c_str());
+        }
+        target->destructible->takeDamage(target, power);
+    }
+    else {
+        printf("%s attacks %s in vain.\n", owner->name.c_str(), target->name.c_str());
+    }
+}
diff --git a/Attacker.h b/Attacker.h
new file mode 100644
index 0000000..142f936
--- /dev/null
+++ b/Attacker.h
@@ -0,0 +1,11 @@
+#pragma once
+
+class Actor;
+
+class Attacker {
+public:
+    float power; // hit points given
+
+    Attacker(float power);
+    void attack(Actor* owner, Actor* target);
+};
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d81d478..2715bcb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,7 @@ project ("ADG5")
 find_package(libtcod CONFIG REQUIRED)
 
 # Add source to this project's executable.
-add_executable (ADG5 "ADG5.cpp" "ADG5.h" "Actor.cpp" "Actor.h" "Map.h" "Map.cpp" "Engine.h" "Engine.cpp" )
+add_executable (ADG5 "ADG5.cpp" "ADG5.h" "Actor.cpp" "Actor.h" "Map.h" "Map.cpp" "Engine.h" "Engine.cpp" "Destructible.h" "Destructible.cpp" "Attacker.h" "Attacker.cpp" "Ai.h" "Ai.cpp")
 
 target_link_libraries(ADG5
   PRIVATE
diff --git a/Destructible.cpp b/Destructible.cpp
new file mode 100644
index 0000000..3988182
--- /dev/null
+++ b/Destructible.cpp
@@ -0,0 +1,52 @@
+#include "Destructible.h"
+#include "Actor.h"
+#include "Engine.h"
+
+Destructible::Destructible(float maxHp, float defense, std::string corpseName) :
+    maxHp(maxHp), hp(maxHp), defense(defense), corpseName(corpseName) {
+}
+
+float Destructible::takeDamage(Actor* owner, float damage) {
+    damage -= defense;
+    if (damage > 0) {
+        hp -= damage;
+        if (hp <= 0) {
+            die(owner);
+        }
+    }
+    else {
+        damage = 0;
+    }
+    return damage;
+}
+
+void Destructible::die(Actor* owner) {
+    // transform the actor into a corpse!
+    owner->ch = "%";
+    owner->col = TCOD_ColorRGB(100, 0, 0);
+    owner->name = corpseName;
+    owner->blocks = false;
+    // make sure corpses are drawn before living actors
+    engine->sendToBack(owner);
+}
+
+MonsterDestructible::MonsterDestructible(float maxHp, float defense, std::string corpseName) :
+    Destructible(maxHp, defense, corpseName) {
+}
+
+PlayerDestructible::PlayerDestructible(float maxHp, float defense, std::string corpseName) :
+    Destructible(maxHp, defense, corpseName) {
+}
+
+void MonsterDestructible::die(Actor* owner) {
+    // transform it into a nasty corpse! it doesn't block, can't be
+    // attacked and doesn't move
+    printf("%s is dead\n", owner->name.c_str());
+    Destructible::die(owner);
+}
+
+void PlayerDestructible::die(Actor* owner) {
+    printf("You died!\n");
+    Destructible::die(owner);
+    engine->gameStatus = Engine::DEFEAT;
+}
\ No newline at end of file
diff --git a/Destructible.h b/Destructible.h
new file mode 100644
index 0000000..a68079f
--- /dev/null
+++ b/Destructible.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+class Actor;
+
+class Destructible {
+public:
+    float maxHp; // maximum health points
+    float hp; // current health points
+    float defense; // hit points deflected
+    std::string corpseName; // the actor's name once dead/destroyed
+
+    Destructible(float maxHp, float defense, std::string corpseName);
+    inline bool isDead() { return hp <= 0; }
+    float takeDamage(Actor* owner, float damage);
+    virtual void die(Actor* owner);
+
+
+};
+
+class MonsterDestructible : public Destructible {
+public:
+    MonsterDestructible(float maxHp, float defense, std::string corpseName);
+    void die(Actor* owner);
+};
+
+class PlayerDestructible : public Destructible {
+public:
+    PlayerDestructible(float maxHp, float defense, std::string corpseName);
+    void die(Actor* owner);
+};
\ No newline at end of file
diff --git a/Engine.cpp b/Engine.cpp
index 1beeac4..a968d01 100644
--- a/Engine.cpp
+++ b/Engine.cpp
@@ -3,20 +3,29 @@
 #include "Actor.h"
 #include "Map.h"
 #include "Engine.h"
+#include "Destructible.h"
+#include "Attacker.h"
+#include "Ai.h"
 
-
-
-Engine::Engine(tcod::Context *context, tcod::Console *console) {
+Engine::Engine(int screenWidth, int screenHeight, tcod::Context *context, tcod::Console *console) {
 	this->context = context;
 	this->console = console;
+	this->screenWidth = screenWidth;
+	this->screenHeight = screenHeight;
+
 	map = nullptr;
 	player = nullptr;
 	fovRadius = 10;
 	computeFov = true;
+	gameStatus = STARTUP;
 }
 
 void Engine::init() {
-	player = new Actor(40, 25, "@", TCOD_ColorRGB(255, 255, 255));
+
+	player = new Actor(40, 25, "@", "player", TCOD_ColorRGB(255, 255, 255));
+	player->destructible = new PlayerDestructible(30, 2, "player corpse");
+	player->attacker = new Attacker(5);
+	player->ai = new PlayerAi();
 	actors.push(player);
 	map = new Map(80, 45);
 }
@@ -27,50 +36,21 @@ Engine::~Engine() {
 }
 
 bool Engine::update() {
-	SDL_Event event;
-	while (SDL_PollEvent(&event)) {
-		context->convert_event_coordinates(event);
-		switch (event.type) {
-		case SDL_EVENT_KEY_DOWN:
-			switch (event.key.key) {
-			case SDLK_UP:
-				if (!map->isWall(player->x, player->y - 1)) {
-					player->y--;
-					computeFov = true;
-				}
-				break;
-			case SDLK_DOWN:
-				if (!map->isWall(player->x, player->y + 1)) {
-					player->y++;
-					computeFov = true;
-				}
-				break;
-			case SDLK_LEFT:
-				if (!map->isWall(player->x - 1, player->y)) {
-					player->x--;
-					computeFov = true;
-				}
-				break;
-			case SDLK_RIGHT:
-				if (!map->isWall(player->x + 1, player->y)) {
-					player->x++;
-					computeFov = true;
-				}
-				break;
-			default:
-				break;
-			}
-			break;
-		case SDL_EVENT_QUIT:
-			return false;
-		default:
-			break;
-		}
-		if (computeFov) {
-			map->computeFov();
-			computeFov = false;
-		}
+	if (gameStatus == STARTUP) map->computeFov();
+	gameStatus = IDLE;
 
+	player->update();
+	if (gameStatus == NEW_TURN) {
+		for (Actor** iterator = actors.begin(); iterator != actors.end();
+			iterator++) {
+			Actor* actor = *iterator;
+			if (actor != player) {
+				actor->update();
+			}
+		}
+	}
+	if (gameStatus == QUIT) {
+		return false;
 	}
 	return true;
 }
@@ -84,9 +64,19 @@ void Engine::render() {
 	for (Actor** iterator = actors.begin();
 		iterator != actors.end(); iterator++) {
 		Actor* actor = *iterator;
-		if (map->isInFov(actor->x, actor->y)) {
+		if (actor != player && map->isInFov(actor->x, actor->y)) {
 			actor->render(*console);
 		}
 	}
+	player->render(*console);
+
+	std::string hp = "HP : " + std::to_string(player->destructible->hp) + "/" + std::to_string(player->destructible->maxHp);
+
+	tcod::print(*console, { 1, 1 }, hp, TCOD_ColorRGB(255, 255, 255), std::nullopt);
 	context->present(*console);
 }
+
+void Engine::sendToBack(Actor* actor) {
+	actors.remove(actor);
+	actors.insertBefore(actor, 0);
+}
\ No newline at end of file
diff --git a/Engine.h b/Engine.h
index 6c725fb..1dc7283 100644
--- a/Engine.h
+++ b/Engine.h
@@ -6,17 +6,30 @@ class Map;
 
 class Engine {
 public:
+    enum GameStatus {
+        STARTUP,
+        IDLE,
+        NEW_TURN,
+        VICTORY,
+        DEFEAT,
+        QUIT
+    } gameStatus;
+
+    int screenWidth;
+	int screenHeight;
+
     TCODList<Actor*> actors;
     Actor* player;
     Map* map;
     int fovRadius;
     tcod::Context *context;
     tcod::Console* console;
-    Engine(tcod::Context *context, tcod::Console *console);
+    Engine(int screenWidth, int screenHeight, tcod::Context *context, tcod::Console *console);
     void init();
     ~Engine();
     bool update();
     void render();
+    void sendToBack(Actor* actor);
 private:
     bool computeFov;
 };
diff --git a/Map.cpp b/Map.cpp
index 6e9b933..0715834 100644
--- a/Map.cpp
+++ b/Map.cpp
@@ -2,9 +2,14 @@
 #include "Map.h"
 #include "Actor.h"
 #include "Engine.h"
+#include "Destructible.h"
+#include "Attacker.h"
+#include "Ai.h"
+
 
 static const int ROOM_MAX_SIZE = 12;
 static const int ROOM_MIN_SIZE = 6;
+static const int MAX_ROOM_MONSTERS = 3;
 
 class BspListener : public ITCODBspCallback {
 private:
@@ -50,6 +55,21 @@ Map::~Map() {
     delete[] tiles;
     delete map;
 }
+bool Map::canWalk(int x, int y) const {
+    if (isWall(x, y)) {
+        // this is a wall
+        return false;
+    }
+    for (Actor** iterator = engine->actors.begin();
+        iterator != engine->actors.end();iterator++) {
+        Actor* actor = *iterator;
+        if (actor->blocks && actor->x == x && actor->y == y) {
+            // there is an actor there. cannot walk
+            return false;
+        }
+    }
+    return true;
+}
 
 bool Map::isInFov(int x, int y) const {
     if (map->isInFov(x, y)) {
@@ -122,9 +142,36 @@ void Map::createRoom(bool first, int x1, int y1, int x2, int y2) {
     }
     else {
         TCODRandom* rng = TCODRandom::getInstance();
-        if (rng->getInt(0, 3) == 0) {
-            engine->actors.push(new Actor((x1 + x2) / 2, (y1 + y2) / 2, "@",
-                TCOD_ColorRGB(255, 255, 0)));
+        int nbMonsters = rng->getInt(0, MAX_ROOM_MONSTERS);
+        while (nbMonsters > 0) {
+            int x = rng->getInt(x1, x2);
+            int y = rng->getInt(y1, y2);
+            if (canWalk(x, y)) {
+                addMonster(x, y);
+            }
+            nbMonsters--;
         }
     }
+}
+
+void Map::addMonster(int x, int y) {
+    TCODRandom* rng = TCODRandom::getInstance();
+    if (rng->getInt(0, 100) < 80) {
+        // create an orc
+        Actor* orc = new Actor(x, y, "o", "orc",
+            TCOD_ColorRGB(0, 100, 0));
+        orc->destructible = new MonsterDestructible(10, 0, "dead orc");
+        orc->attacker = new Attacker(3);
+        orc->ai = new MonsterAi();
+        engine->actors.push(orc);
+    }
+    else {
+        // create a troll
+        Actor* troll = new Actor(x, y, "T", "troll",
+            TCOD_ColorRGB(0, 255, 0));
+        troll->destructible = new MonsterDestructible(16, 1, "troll carcass");
+        troll->attacker = new Attacker(4);
+        troll->ai = new MonsterAi();
+        engine->actors.push(troll);
+    }
 }
\ No newline at end of file
diff --git a/Map.h b/Map.h
index b3f7ae3..b6c76e8 100644
--- a/Map.h
+++ b/Map.h
@@ -11,6 +11,7 @@ public:
 
     Map(int width, int height);
     ~Map();
+    bool canWalk(int x, int y) const;
     bool isWall(int x, int y) const;
     bool isInFov(int x, int y) const;
     bool isExplored(int x, int y) const;
@@ -22,6 +23,6 @@ protected:
     TCODMap* map;
     void dig(int x1, int y1, int x2, int y2);
     void createRoom(bool first, int x1, int y1, int x2, int y2);
-
+    void addMonster(int x, int y);
     void setWall(int x, int y);
 };
\ No newline at end of file