diff --git a/data/json/monsters/bird.json b/data/json/monsters/bird.json
index 6b3e2e45d8ba..dd178c578865 100644
--- a/data/json/monsters/bird.json
+++ b/data/json/monsters/bird.json
@@ -108,11 +108,16 @@
     "type": "MONSTER",
     "copy-from": "mon_duck",
     "name": { "str": "goose", "str_pl": "geese" },
+    "aggression": 0,
+    "morale": 15,
+    "aggro_character": false,
     "description": "A Canadian goose, a common waterfowl that regrets leaving Canada.",
     "volume": "5 L",
     "weight": "3750 g",
     "hp": 15,
     "dodge": 3,
+    "anger_triggers": [ "PLAYER_CLOSE", "FRIEND_ATTACKED" ],
+    "fear_triggers": [ "FRIEND_DIED", "FIRE" ],
     "reproduction": { "baby_egg": "egg_goose_canadian", "baby_count": 3, "baby_timer": 10 },
     "baby_flags": [ "SPRING" ]
   },
diff --git a/data/json/monsters/fish.json b/data/json/monsters/fish.json
index 7fe0066845d2..5b6544579c95 100644
--- a/data/json/monsters/fish.json
+++ b/data/json/monsters/fish.json
@@ -15,6 +15,7 @@
     "material": [ "flesh" ],
     "symbol": "Y",
     "color": "red",
+    "aggro_character": false,
     "aggression": 15,
     "morale": 100,
     "melee_skill": 6,
@@ -645,6 +646,7 @@
     "material": [ "flesh" ],
     "symbol": "Y",
     "color": "magenta",
+    "aggro_character": false,
     "aggression": 4,
     "morale": 100,
     "melee_skill": 6,
diff --git a/data/json/monsters/insect_spider.json b/data/json/monsters/insect_spider.json
index 796c4b305840..23a8c156c99c 100644
--- a/data/json/monsters/insect_spider.json
+++ b/data/json/monsters/insect_spider.json
@@ -326,6 +326,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "yellow",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 20,
     "melee_skill": 4,
@@ -367,6 +368,7 @@
     "hp": 15,
     "speed": 115,
     "attack_cost": 115,
+    "aggro_character": false,
     "aggression": 0,
     "morale": 0,
     "melee_skill": 5,
@@ -406,6 +408,7 @@
     "hp": 35,
     "speed": 110,
     "attack_cost": 110,
+    "aggro_character": false,
     "aggression": 9,
     "morale": 20,
     "melee_skill": 6,
@@ -451,6 +454,7 @@
     "volume": "300 L",
     "weight": "400 kg",
     "speed": 60,
+    "aggro_character": false,
     "aggression": 0,
     "morale": 10,
     "melee_skill": 3,
@@ -499,6 +503,7 @@
     "hp": 125,
     "speed": 110,
     "attack_cost": 110,
+    "aggro_character": false,
     "aggression": 100,
     "regen_morale": true,
     "melee_skill": 6,
@@ -746,6 +751,7 @@
     "material": [ "iflesh" ],
     "symbol": "s",
     "color": "brown",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 100,
     "melee_skill": 6,
@@ -815,6 +821,7 @@
     "material": [ "iflesh" ],
     "symbol": "s",
     "color": "white",
+    "aggro_character": false,
     "aggression": -20,
     "morale": 80,
     "melee_skill": 5,
@@ -882,6 +889,7 @@
     "material": [ "iflesh" ],
     "symbol": "s",
     "color": "yellow",
+    "aggro_character": false,
     "aggression": 20,
     "morale": 100,
     "melee_skill": 4,
@@ -914,6 +922,7 @@
     "material": [ "iflesh" ],
     "symbol": "c",
     "color": "yellow",
+    "aggro_character": false,
     "aggression": 20,
     "morale": 100,
     "melee_skill": 1,
@@ -946,6 +955,7 @@
     "material": [ "iflesh" ],
     "symbol": "s",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 100,
     "melee_skill": 6,
@@ -980,6 +990,7 @@
     "material": [ "iflesh" ],
     "symbol": "c",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 100,
     "melee_skill": 4,
@@ -1013,6 +1024,7 @@
     "material": [ "iflesh" ],
     "symbol": "s",
     "color": "brown",
+    "aggro_character": false,
     "aggression": 20,
     "morale": 100,
     "melee_skill": 5,
@@ -1086,6 +1098,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": -10,
     "melee_skill": 5,
     "melee_dice": 2,
@@ -1171,6 +1184,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": -5,
     "morale": 15,
     "melee_skill": 7,
@@ -1421,6 +1435,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "brown",
+    "aggro_character": false,
     "morale": 60,
     "melee_skill": 5,
     "melee_dice": 1,
@@ -1456,6 +1471,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "green",
+    "aggro_character": false,
     "morale": 60,
     "melee_skill": 5,
     "melee_dice": 1,
@@ -1548,6 +1564,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "brown",
+    "aggro_character": false,
     "aggression": 40,
     "morale": 100,
     "melee_skill": 7,
@@ -1638,6 +1655,7 @@
     "material": [ "iflesh" ],
     "symbol": "a",
     "color": "red",
+    "aggro_character": false,
     "aggression": 30,
     "morale": 100,
     "melee_skill": 7,
diff --git a/data/json/monsters/mammal.json b/data/json/monsters/mammal.json
index b59aee9c4edc..3f5e84c60709 100644
--- a/data/json/monsters/mammal.json
+++ b/data/json/monsters/mammal.json
@@ -67,6 +67,7 @@
     "material": [ "flesh" ],
     "symbol": "B",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 60,
     "melee_skill": 6,
@@ -107,6 +108,7 @@
     "material": [ "flesh" ],
     "symbol": "r",
     "color": "brown",
+    "aggro_character": false,
     "aggression": -35,
     "morale": 15,
     "melee_dice": 1,
@@ -135,6 +137,7 @@
     "material": [ "flesh" ],
     "symbol": "r",
     "color": "dark_gray",
+    "aggro_character": false,
     "aggression": 5,
     "morale": 5,
     "melee_skill": 5,
@@ -169,6 +172,7 @@
     "symbol": "b",
     "color": "brown",
     "looks_like": "mon_pig_piglet",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 10,
     "melee_skill": 1,
@@ -202,6 +206,7 @@
     "material": [ "flesh" ],
     "symbol": "b",
     "color": "brown",
+    "aggro_character": false,
     "aggression": 20,
     "morale": 40,
     "melee_skill": 5,
@@ -239,6 +244,7 @@
     "material": [ "flesh" ],
     "symbol": "c",
     "color": "brown",
+    "aggro_character": false,
     "aggression": -25,
     "morale": 1,
     "melee_skill": 6,
@@ -661,6 +667,7 @@
     "material": [ "flesh" ],
     "symbol": "C",
     "color": "light_gray",
+    "aggro_character": false,
     "aggression": -50,
     "morale": 60,
     "melee_skill": 6,
@@ -835,6 +842,7 @@
     "material": [ "flesh" ],
     "symbol": "d",
     "color": "light_gray",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 15,
     "melee_skill": 6,
@@ -881,6 +889,7 @@
     "weight": "1 kg",
     "hp": 8,
     "speed": 98,
+    "aggro_character": false,
     "aggression": -13,
     "morale": 8,
     "melee_skill": 2,
@@ -1699,6 +1708,7 @@
     "material": [ "flesh" ],
     "symbol": "d",
     "color": "light_gray",
+    "aggro_character": false,
     "aggression": -5,
     "morale": 30,
     "melee_skill": 3,
@@ -1730,6 +1740,7 @@
     "material": [ "flesh" ],
     "symbol": "d",
     "color": "red",
+    "aggro_character": false,
     "aggression": -5,
     "morale": 60,
     "melee_skill": 4,
@@ -1848,6 +1859,7 @@
     "material": [ "flesh" ],
     "symbol": "H",
     "color": "brown",
+    "aggro_character": false,
     "melee_skill": 6,
     "melee_dice": 2,
     "melee_dice_sides": 12,
@@ -1937,6 +1949,7 @@
     "material": [ "flesh" ],
     "symbol": "M",
     "color": "brown",
+    "aggro_character": false,
     "aggression": 5,
     "morale": 80,
     "melee_skill": 6,
@@ -2131,6 +2144,7 @@
     "material": [ "flesh" ],
     "symbol": "p",
     "color": "pink",
+    "aggro_character": false,
     "aggression": 10,
     "morale": 30,
     "melee_skill": 4,
@@ -2248,6 +2262,7 @@
     "material": [ "flesh" ],
     "symbol": "r",
     "color": "light_gray",
+    "aggro_character": false,
     "aggression": 20,
     "morale": 40,
     "melee_skill": 5,
@@ -2425,6 +2440,7 @@
     "material": [ "flesh" ],
     "symbol": "w",
     "color": "light_gray",
+    "aggro_character": false,
     "morale": 20,
     "melee_skill": 7,
     "melee_dice": 2,
diff --git a/data/json/monsters/mutant_animal.json b/data/json/monsters/mutant_animal.json
index e65b82c32a4a..663c06a37c90 100644
--- a/data/json/monsters/mutant_animal.json
+++ b/data/json/monsters/mutant_animal.json
@@ -6,6 +6,7 @@
     "description": "As it moves, this cat's colors shift unnaturally in the light.  You can't make out the breed, but its fur pattern seems to change with every step.",
     "copy-from": "mon_cat",
     "luminance": 5,
+    "aggro_character": false,
     "//": "Higher dodge due to the constantly changing fur pattern",
     "dodge": 9,
     "reproduction": { "baby_monster": "mon_cat_mutant_kitten_prism", "baby_count": 2, "baby_timer": 80 },
@@ -109,6 +110,7 @@
     "symbol": "B",
     "color": "dark_gray",
     "looks_like": "mon_bear",
+    "aggro_character": false,
     "morale": 60,
     "melee_skill": 6,
     "melee_dice": 4,
@@ -151,6 +153,7 @@
     "symbol": "r",
     "color": "brown",
     "looks_like": "mon_beaver",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 20,
     "melee_dice": 2,
@@ -181,6 +184,7 @@
     "symbol": "r",
     "color": "brown",
     "looks_like": "mon_beaver",
+    "aggro_character": false,
     "aggression": -50,
     "morale": 5,
     "melee_dice": 1,
@@ -407,6 +411,7 @@
     "symbol": "d",
     "color": "light_gray",
     "looks_like": "mon_dog",
+    "aggro_character": false,
     "aggression": -15,
     "morale": 15,
     "melee_skill": 6,
diff --git a/data/json/monsters/mutant_human.json b/data/json/monsters/mutant_human.json
index a0442be37f23..9a358652ccc0 100644
--- a/data/json/monsters/mutant_human.json
+++ b/data/json/monsters/mutant_human.json
@@ -47,6 +47,7 @@
     "symbol": "M",
     "color": "brown",
     "morale": 50,
+    "aggro_character": false,
     "melee_skill": 6,
     "melee_dice": 3,
     "melee_dice_sides": 6,
diff --git a/data/json/monsters/reptile_amphibian.json b/data/json/monsters/reptile_amphibian.json
index 0d46cb9dd04f..41782581b36b 100644
--- a/data/json/monsters/reptile_amphibian.json
+++ b/data/json/monsters/reptile_amphibian.json
@@ -14,6 +14,7 @@
     "material": [ "flesh" ],
     "symbol": "M",
     "color": "light_green",
+    "aggro_character": false,
     "aggression": 10,
     "morale": 100,
     "melee_skill": 5,
@@ -95,6 +96,7 @@
     "material": [ "flesh" ],
     "symbol": "s",
     "color": "brown",
+    "aggro_character": false,
     "aggression": -50,
     "morale": 60,
     "melee_skill": 5,
@@ -129,6 +131,7 @@
     "material": [ "flesh" ],
     "symbol": "s",
     "color": "brown",
+    "aggro_character": false,
     "aggression": -10,
     "morale": 60,
     "melee_skill": 6,
diff --git a/doc/src/content/docs/en/mod/json/reference/creatures/monsters.md b/doc/src/content/docs/en/mod/json/reference/creatures/monsters.md
index fa32a2afc808..184acc03f23f 100644
--- a/doc/src/content/docs/en/mod/json/reference/creatures/monsters.md
+++ b/doc/src/content/docs/en/mod/json/reference/creatures/monsters.md
@@ -218,6 +218,14 @@ hostility on detection)
 Monster morale. Defines how low monster HP can get before it retreats. This number is treated as %
 of their max HP.
 
+## "aggro_character"
+
+(bool, optional, default true)
+
+If the monster will differentiate between monsters and characters (NPC, Player) when deciding on
+targets - if false the monster will ignore characters regardless of current anger/morale until a
+character trips and anger trigger. Resets randomly when the monster is at its base anger level.
+
 ## "speed"
 
 (integer)
diff --git a/doc/src/content/docs/en/mod/json/reference/json_flags.md b/doc/src/content/docs/en/mod/json/reference/json_flags.md
index c96ddd250869..f3ff937630d1 100644
--- a/doc/src/content/docs/en/mod/json/reference/json_flags.md
+++ b/doc/src/content/docs/en/mod/json/reference/json_flags.md
@@ -940,12 +940,13 @@ Flags used to describe monsters and define their properties and abilities.
 ### Anger, Fear and Placation Triggers
 
 - `FIRE` There's a fire nearby.
-- `FRIEND_ATTACKED` A monster of the same type was attacked.
-- `FRIEND_DIED` A monster of the same type died.
-- `HURT` The monster is hurt.
+- `FRIEND_ATTACKED` A monster of the same type was attacked. Always triggers character aggro.
+- `FRIEND_DIED` A monster of the same type died. Always triggers character aggro.
+- `HURT` The monster is hurt. Always triggers character aggro.
 - `MEAT` Meat or a corpse is nearby.
 - `NULL` Source use only?
-- `PLAYER_CLOSE` The player gets within a few tiles distance.
+- `PLAYER_CLOSE` The player gets within a few tiles distance. Triggers character aggro `<anger>%` of
+  the time.
 - `PLAYER_WEAK` The player is hurt.
 - `SOUND` Heard a sound.
 - `STALK` Increases when following the player.
diff --git a/src/mattack_actors.cpp b/src/mattack_actors.cpp
index 9234b133e15e..fe240468d8c0 100644
--- a/src/mattack_actors.cpp
+++ b/src/mattack_actors.cpp
@@ -579,7 +579,7 @@ bool gun_actor::call( monster &z ) const
         aim_at = target->pos();
     } else {
         target = z.attack_target();
-        if( !target || !z.sees( *target ) ) {
+        if( !target || ( !target->is_monster() && !z.aggro_character ) || !z.sees( *target ) ) {
             if( !target_moving_vehicles ) {
                 return false;
             }
diff --git a/src/monmove.cpp b/src/monmove.cpp
index b526d5c79d98..674496a6080d 100644
--- a/src/monmove.cpp
+++ b/src/monmove.cpp
@@ -354,6 +354,9 @@ void monster::plan()
         target = &g->u;
         if( dist <= 5 ) {
             anger += angers_hostile_near;
+            if( angers_hostile_near ) {
+                trigger_character_aggro_chance( anger, "proximity" );
+            }
             morale -= fears_hostile_near;
             if( angers_mating_season > 0 ) {
                 bool mating_angry = false;
@@ -369,6 +372,7 @@ void monster::plan()
                 }
                 if( mating_angry ) {
                     anger += angers_mating_season;
+                    trigger_character_aggro_chance( anger, "mating season" );
                 }
             }
         }
@@ -381,6 +385,7 @@ void monster::plan()
                         //proximity to baby; monster gets furious and less likely to flee
                         anger += angers_cub_threatened;
                         morale += angers_cub_threatened / 2;
+                        trigger_character_aggro( "threatening cub" );
                     }
                 }
             }
@@ -444,6 +449,7 @@ void monster::plan()
                 }
                 if( mating_angry ) {
                     anger += angers_mating_season;
+                    trigger_character_aggro_chance( anger, "mating season" );
                 }
             }
         }
@@ -586,6 +592,9 @@ void monster::plan()
             int hp_per = target->hp_percentage();
             if( hp_per <= 70 ) {
                 anger += 10 - ( hp_per / 10 );
+                if( anger <= 40 ) {
+                    trigger_character_aggro_chance( anger, "weakness" );
+                }
             }
         }
     } else if( friendly > 0 && one_in( 3 ) ) {
diff --git a/src/monster.cpp b/src/monster.cpp
index 85e368dab082..b8bf6545e6b8 100644
--- a/src/monster.cpp
+++ b/src/monster.cpp
@@ -222,6 +222,7 @@ monster::monster() : corpse_components( new monster_component_item_location( thi
     last_updated = calendar::start_of_cataclysm;
     udder_timer = calendar::turn;
     horde_attraction = MHA_NULL;
+    aggro_character = true;
     set_anatomy( anatomy_id( "default_anatomy" ) );
     set_body();
 }
@@ -242,6 +243,7 @@ monster::monster( const mtype_id &id ) : monster()
     ammo = type->starting_ammo;
     upgrades = type->upgrades && ( type->half_life || type->age_grow );
     reproduces = type->reproduces && type->baby_timer && !monster::has_flag( MF_NO_BREED );
+    aggro_character = type->aggro_character;
     if( monster::has_flag( MF_AQUATIC ) ) {
         fish_population = dice( 1, 20 );
     }
@@ -1452,13 +1454,13 @@ monster_attitude monster::attitude( const Character *u ) const
         }
     }
 
+
     if( effective_morale < 0 ) {
         if( effective_morale + effective_anger > 0 && get_hp() > get_hp_max() / 3 ) {
             return MATT_FOLLOW;
         }
         return MATT_FLEE;
     }
-
     if( effective_anger <= 0 ) {
         if( get_hp() <= 0.6 * get_hp_max() ) {
             return MATT_FLEE;
@@ -1471,6 +1473,10 @@ monster_attitude monster::attitude( const Character *u ) const
         return MATT_FOLLOW;
     }
 
+    if( u != nullptr && !aggro_character && !u->is_monster() ) {
+        return MATT_IGNORE;
+    }
+
     return MATT_ATTACK;
 }
 
@@ -1513,6 +1519,12 @@ void monster::process_triggers()
         }
     }
 
+    // If we got angry at characters have a chance at calming down
+    if( anger == type->agro && aggro_character && !type->aggro_character && !x_in_y( anger, 100 ) ) {
+        add_msg( m_debug, "%s's character aggro reset", get_name() );
+        aggro_character = false;
+    }
+
     // Cap values at [-100, 100] to prevent perma-angry moose etc.
     morale = std::min( 100, std::max( -100, morale ) );
     anger  = std::min( 100, std::max( -100, anger ) );
@@ -1545,6 +1557,22 @@ void monster::process_trigger( mon_trigger trig, const std::function<int()> &amo
     }
 }
 
+
+// hopefully a good spot for these functions
+// eg. reason = "mating season"
+void monster::trigger_character_aggro( const char *reason )
+{
+    add_msg( m_debug, "%s's character aggro is triggered by %s", get_name(), reason );
+    aggro_character = true;
+}
+
+void monster::trigger_character_aggro_chance( int chance, const char *reason )
+{
+    if( x_in_y( chance, 100 ) ) {
+        trigger_character_aggro( reason );
+    }
+}
+
 bool monster::is_underwater() const
 {
     return Creature::is_underwater() && can_submerge();
@@ -1947,6 +1975,10 @@ void monster::apply_damage( Creature *source, item *source_weapon, item *source_
         }
     } else if( dam > 0 ) {
         process_trigger( mon_trigger::HURT, 1 + ( dam / 3 ) );
+        // Get angry at characters if hurt by one
+        if( source != nullptr && !aggro_character && !source->is_monster() && !source->is_fake() ) {
+            trigger_character_aggro( "hurt" );
+        }
     }
 }
 void monster::apply_damage( Creature *source, item *source_weapon, bodypart_id bp, int dam,
@@ -2679,6 +2711,10 @@ void monster::die( Creature *nkiller )
     int morale_adjust = 0;
     if( type->has_anger_trigger( mon_trigger::FRIEND_DIED ) ) {
         anger_adjust += 15;
+        if( nkiller != nullptr && !nkiller->is_monster() && !nkiller->is_fake() ) {
+            // A character killed our friend
+            trigger_character_aggro( "killing a friendly creature" );
+        }
     }
     if( type->has_fear_trigger( mon_trigger::FRIEND_DIED ) ) {
         morale_adjust -= 15;
@@ -3178,6 +3214,10 @@ void monster::on_hit( Creature *source, bodypart_id, dealt_projectile_attack con
     int morale_adjust = 0;
     if( type->has_anger_trigger( mon_trigger::FRIEND_ATTACKED ) ) {
         anger_adjust += 15;
+        if( source != nullptr && !aggro_character && !source->is_monster() && !source->is_fake() ) {
+            // A character attacked our friend
+            trigger_character_aggro( "killing a friendly creature" );
+        }
     }
     if( type->has_fear_trigger( mon_trigger::FRIEND_ATTACKED ) ) {
         morale_adjust -= 15;
@@ -3344,6 +3384,36 @@ void monster::on_load()
     if( dt <= 0_turns ) {
         return;
     }
+
+    if( anger != type->agro ) {
+        int dt_left_a = to_turns<int>( dt );
+
+        if( std::abs( anger - type->agro ) > 15 ) {
+            const int adjust_by_a = std::min( ( dt_left_a / 4 ),
+                                              ( std::abs( anger - type->agro ) - 15 ) );
+            dt_left_a -= adjust_by_a * 4;
+            if( anger < type->agro ) {
+                anger += adjust_by_a;
+            } else {
+                anger -= adjust_by_a;
+            }
+        }
+
+        if( anger > type->agro ) {
+            anger -= std::min( static_cast<int>( std::ceil( dt_left_a / 8.0 ) ),
+                               std::abs( anger - type->agro ) );
+        } else {
+            anger += std::min( ( dt_left_a / 8 ),
+                               std::abs( anger - type->agro ) );
+        }
+        // If we got angry at characters have a chance at calming down
+        if( aggro_character && !type->aggro_character && !x_in_y( anger, 100 ) ) {
+            add_msg( m_debug, "%s's character aggro reset", name() );
+            aggro_character = false;
+        }
+    }
+
+
     float regen = type->regenerates;
     if( regen <= 0 ) {
         if( has_flag( MF_REVIVES ) ) {
diff --git a/src/monster.h b/src/monster.h
index 18d6cb72e161..8f339a558ad6 100644
--- a/src/monster.h
+++ b/src/monster.h
@@ -532,6 +532,9 @@ class monster : public Creature, public location_visitable<monster>
         }
 
         short ignoring;
+
+        bool aggro_character = true;
+
         std::optional<time_point> lastseen_turn;
 
         // Stair data.
@@ -601,6 +604,9 @@ class monster : public Creature, public location_visitable<monster>
         void process_trigger( mon_trigger trig, int amount );
         void process_trigger( mon_trigger trig, const std::function<int()> &amount_func );
 
+        void trigger_character_aggro( const char *reason );
+        void trigger_character_aggro_chance( int chance, const char *reason );
+
         location_vector<item> corpse_components; // Hack to make bionic corpses generate CBMs on death
 
     private:
@@ -624,6 +630,7 @@ class monster : public Creature, public location_visitable<monster>
         std::bitset<NUM_MEFF> effect_cache;
         std::optional<time_duration> summon_time_limit = std::nullopt;
 
+
         player *find_dragged_foe();
         void nursebot_operate( player *dragged_foe );
 
diff --git a/src/monstergenerator.cpp b/src/monstergenerator.cpp
index 01f1c5300cb1..cead2bf257f9 100644
--- a/src/monstergenerator.cpp
+++ b/src/monstergenerator.cpp
@@ -821,6 +821,7 @@ void mtype::load( const JsonObject &jo, const std::string &src )
     optional( jo, was_loaded, "mech_weapon", mech_weapon, itype_id() );
     optional( jo, was_loaded, "mech_str_bonus", mech_str_bonus, 0 );
     optional( jo, was_loaded, "mech_battery", mech_battery, itype_id() );
+    optional( jo, was_loaded, "aggro_character", aggro_character, true );
 
     // TODO: make this work with `was_loaded`
     if( jo.has_array( "melee_damage" ) ) {
diff --git a/src/mtype.cpp b/src/mtype.cpp
index ac37d6aa9556..fc340a804403 100644
--- a/src/mtype.cpp
+++ b/src/mtype.cpp
@@ -56,6 +56,8 @@ mtype::mtype()
     luminance = 0;
     bash_skill = 0;
 
+    aggro_character = true;
+
     flags
     .set( MF_HUMAN )
     .set( MF_BONES )
diff --git a/src/mtype.h b/src/mtype.h
index 4127cd5ba011..2345ffc27776 100644
--- a/src/mtype.h
+++ b/src/mtype.h
@@ -370,6 +370,9 @@ struct mtype {
         bool upgrades;
         bool reproduces;
 
+        // Do we indiscriminately attack characters, or should we wait until one annoys us?
+        bool aggro_character = true;
+
         mtype();
         /**
          * Check if this type is of the same species as the other one, because
diff --git a/src/savegame_json.cpp b/src/savegame_json.cpp
index a1be2df9c56d..c32f349db388 100644
--- a/src/savegame_json.cpp
+++ b/src/savegame_json.cpp
@@ -1843,6 +1843,7 @@ void monster::load( const JsonObject &data )
     data.read( "anger", anger );
     data.read( "morale", morale );
     data.read( "hallucination", hallucination );
+    data.read( "aggro_character", aggro_character );
     data.read( "stairscount", staircount ); // really?
     data.read( "fish_population", fish_population );
     // Load legacy plans.
@@ -1935,6 +1936,7 @@ void monster::store( JsonOut &json ) const
     json.member( "anger", anger );
     json.member( "morale", morale );
     json.member( "hallucination", hallucination );
+    json.member( "aggro_character", aggro_character );
     json.member( "stairscount", staircount );
     if( tied_item ) {
         json.member( "tied_item", *tied_item );