What is the default Difficulty game rule in CK3?

Normal: You will play on an even playing field, without any significant bonuses. (patch 1.20.1.2)

Does changing the Difficulty rule disable achievements?

Yes for “Easy” and “Very Easy”: the file gives them the flag blocks_achievements. The other settings keep achievements on.

What does Difficulty: Hard change?

AI rulers get Men-at-Arms Recruitment Cost -50%, Stress Gain -50%, Building Construction Cost -25%, Holding Construction Cost -25%, Domicile Building Construction Cost -25%, Build herd cost -25%, Building Construction Cost -50%, Levy Reinforcement Rate +100%, Sway Phase Length 150 days faster per Scheme Phase, Tyranny Gain -50%, Embarkation Cost -100%, Mercenary Hire Cost -30% and 1 more; Players get Mercenary Hire Cost +50%.

What does Difficulty: Very Hard change?

AI rulers get Men-at-Arms Recruitment Cost -75%, Stress Gain -75%, Building Construction Cost -50%, Holding Construction Cost -50%, Domicile Building Construction Cost -50%, Build herd cost -50%, Building Construction Cost -75%, Levy Reinforcement Rate +300%, Sway Phase Length 250 days faster per Scheme Phase, Tyranny Gain -75%, Embarkation Cost -100%, Mercenary Hire Cost -60% and 2 more; Players get Hostile scheme success chance max -50%, Knight Effectiveness -50%, Mercenary Hire Cost +150%.

What does Difficulty: Easy change?

Players get Health +0.5, Disease Resistance (Health) +0.5, Tyranny Gain -25%, Fertility +10%, Stress Gain -25%, Short Reign Duration -25%, Enemy Hostile Scheme Phase Length 20 days slower per Scheme Phase.

Game rule · Difficulty · AI

Difficulty

Normal · default
Hard
Very Hard
Easy ✕
Very Easy ✕

Difficulty is a game rule in Crusader Kings III (Difficulty and AI) with 5 settings: Normal (the default), Hard, Very Hard, Easy and Very Easy. “Easy” and “Very Easy” disable achievements. 4 settings apply modifiers, e.g. Hard: Men-at-Arms Recruitment Cost -50%, Stress Gain -50%, Building Construction Cost -25%, Holding Construction Cost -25% and 10 more. Patch 1.20.1.2, from game/common/game_rules/00_game_rules.txt.

This section as JSON: /raw/game-rules.json

Quick answers (5)

What is the default Difficulty game rule in CK3?: Normal: You will play on an even playing field, without any significant bonuses. (patch 1.20.1.2)
Does changing the Difficulty rule disable achievements?: Yes for “Easy” and “Very Easy”: the file gives them the flag blocks_achievements. The other settings keep achievements on.
What does Difficulty: Hard change?: AI rulers get Men-at-Arms Recruitment Cost -50%, Stress Gain -50%, Building Construction Cost -25%, Holding Construction Cost -25%, Domicile Building Construction Cost -25%, Build herd cost -25%, Building Construction Cost -50%, Levy Reinforcement Rate +100%, Sway Phase Length 150 days faster per Scheme Phase, Tyranny Gain -50%, Embarkation Cost -100%, Mercenary Hire Cost -30% and 1 more; Players get Mercenary Hire Cost +50%.
What does Difficulty: Very Hard change?: AI rulers get Men-at-Arms Recruitment Cost -75%, Stress Gain -75%, Building Construction Cost -50%, Holding Construction Cost -50%, Domicile Building Construction Cost -50%, Build herd cost -50%, Building Construction Cost -75%, Levy Reinforcement Rate +300%, Sway Phase Length 250 days faster per Scheme Phase, Tyranny Gain -75%, Embarkation Cost -100%, Mercenary Hire Cost -60% and 2 more; Players get Hostile scheme success chance max -50%, Knight Effectiveness -50%, Mercenary Hire Cost +150%.
What does Difficulty: Easy change?: Players get Health +0.5, Disease Resistance (Health) +0.5, Tyranny Gain -25%, Fertility +10%, Stress Gain -25%, Short Reign Duration -25%, Enemy Hostile Scheme Phase Length 20 days slower per Scheme Phase.

5 settings

Normal
Default
You will play on an even playing field, without any significant bonuses.
normal_difficulty
Hard
AI rulers will receive bonuses, such as less stress and more stable realms. This will make AI realms much more stable and rich, which will make the game less balanced.
AI rulers get the modifier hard_difficulty (“Hard”):
- Men-at-Arms Recruitment Cost-50%
- Stress Gain-50%
- Building Construction Cost-25%
- Holding Construction Cost-25%
- Domicile Building Construction Cost-25%
- Build herd cost-25%
- Building Construction Cost-50%
- Levy Reinforcement Rate+100%
- Sway Phase Length150 days faster per Scheme Phase
- Tyranny Gain-50%
- Embarkation Cost-100%
- Mercenary Hire Cost-30%
- Men-at-Arms Maintenance-25%
Players get the modifier hard_difficulty_player (“Hard”):
- Mercenary Hire Cost+50%
The script checks it 85 times, in 57 places
Script values 40
- base_court_amenities_cost
- base_wedding_cost
- common_cb_cost_multiplier_core
- coronation_cost_factor_for_ai
- court_position_antiquarian_salary
- court_position_physician_salary
- court_position_travel_leader_salary
- feast_activity_cost
- funeral_good_option_cost
- funeral_normal_option_cost
- gold_refill_value
- gold_refill_value_tt
- herd_refill_value
- herd_refill_value_tt
- major_court_position_piety_salary
- major_court_position_prestige_salary
- major_court_position_salary
- medium_court_position_piety_salary
- medium_court_position_prestige_salary
- medium_court_position_salary
- minor_court_position_piety_salary
- minor_court_position_prestige_salary
- minor_court_position_salary
- monthly_court_position_task_cost
- normal_ransom_cost_value
- provision_refill_value
- provision_refill_value_tt
- ransom_herd_value
- recruit_guest_interaction_cost_with_list
- standard_activity_base_cost
- standard_playdate_activity_cost
- tiny_court_position_salary
- tournament_base_cost
- tournament_option_bad_cost
- tournament_option_good_cost
- tournament_option_normal_cost
- tournament_option_splendid_cost
- tournament_option_very_good_cost
- vassal_obligation_increase_tyranny_gain
- very_high_court_position_prestige_salary
Scripted effects 5
Scripted modifiers (AI weights) 5
- ai_agent_join_chance_hostile_general_suite_modifier
- ask_for_gold_acceptance_modifier
- common_faction_modifiers
- marriage_ai_accept_modifier
- marriage_ai_accept_politic_modifier
Character interactions 3
Factions 2
- Escalated Peasant Faction
- Peasant Faction
Activities 1
- Grand Tour
Scripted triggers 1
- vassal_would_join_rebel_faction_tyranny_trigger
Every has_game_rule = hard_difficulty in game/common and game/events, by the top-level object it sits in.
hard_difficulty
Very Hard
AI rulers will receive significant bonuses, such as less stress and more stable realms. This will make AI realms extremely stable and rich, which will make the game less balanced.
AI rulers get the modifier very_hard_difficulty (“Very Hard”):
- Men-at-Arms Recruitment Cost-75%
- Stress Gain-75%
- Building Construction Cost-50%
- Holding Construction Cost-50%
- Domicile Building Construction Cost-50%
- Build herd cost-50%
- Building Construction Cost-75%
- Levy Reinforcement Rate+300%
- Sway Phase Length250 days faster per Scheme Phase
- Tyranny Gain-75%
- Embarkation Cost-100%
- Mercenary Hire Cost-60%
- Men-at-Arms Maintenance-50%
- Led by owner extra advantage+10
Players get the modifier very_hard_difficulty_player (“Very Hard”):
- Hostile scheme success chance max-50%
- Knight Effectiveness-50%
- Mercenary Hire Cost+150%
The script checks it 85 times, in 57 places
Script values 40
- base_court_amenities_cost
- base_wedding_cost
- common_cb_cost_multiplier_core
- coronation_cost_factor_for_ai
- court_position_antiquarian_salary
- court_position_physician_salary
- court_position_travel_leader_salary
- feast_activity_cost
- funeral_good_option_cost
- funeral_normal_option_cost
- gold_refill_value
- gold_refill_value_tt
- herd_refill_value
- herd_refill_value_tt
- major_court_position_piety_salary
- major_court_position_prestige_salary
- major_court_position_salary
- medium_court_position_piety_salary
- medium_court_position_prestige_salary
- medium_court_position_salary
- minor_court_position_piety_salary
- minor_court_position_prestige_salary
- minor_court_position_salary
- monthly_court_position_task_cost
- normal_ransom_cost_value
- provision_refill_value
- provision_refill_value_tt
- ransom_herd_value
- recruit_guest_interaction_cost_with_list
- standard_activity_base_cost
- standard_playdate_activity_cost
- tiny_court_position_salary
- tournament_base_cost
- tournament_option_bad_cost
- tournament_option_good_cost
- tournament_option_normal_cost
- tournament_option_splendid_cost
- tournament_option_very_good_cost
- vassal_obligation_increase_tyranny_gain
- very_high_court_position_prestige_salary
Scripted effects 5
Scripted modifiers (AI weights) 5
- ai_agent_join_chance_hostile_general_suite_modifier
- ask_for_gold_acceptance_modifier
- common_faction_modifiers
- marriage_ai_accept_modifier
- marriage_ai_accept_politic_modifier
Character interactions 3
Factions 2
- Escalated Peasant Faction
- Peasant Faction
Activities 1
- Grand Tour
Scripted triggers 1
- vassal_would_join_rebel_faction_tyranny_trigger
Every has_game_rule = very_hard_difficulty in game/common and game/events, by the top-level object it sits in.
very_hard_difficulty
Easy
Disables achievements
You will be given bonuses, such as lessening the impact of disease, hostile schemes and stress. It will also be easier to handle Factions.
Players get the modifier easy_difficulty (“Easy”):
- Health+0.5
- Disease Resistance (Health)+0.5
- Tyranny Gain-25%
- Fertility+10%
- Stress Gain-25%
- Short Reign Duration-25%
- Enemy Hostile Scheme Phase Length20 days slower per Scheme Phase
The script checks it 18 times, in 15 places
Scripted modifiers (AI weights) 6
- ai_agent_join_chance_hostile_general_suite_modifier
- ai_agent_join_chance_hostile_title_modifier
- ai_agent_join_chance_personal_general_suite_modifier
- common_faction_modifiers
- hostile_scheme_base_chance_modifier
- hostile_scheme_title_base_chance_modifier
Script values 3
- disease_outbreak_pulse_chance_of_no_event
- hostile_scheme_base_odds_prediction_guts_value
- outbreak_chance_major_mult_value
Factions 2
- Escalated Peasant Faction
- Peasant Faction
Combat phase events 1
- commander_none
Events 1
- … A Journey's End?
Character interactions 1
- Ask to Join my Movement
Scripted effects 1
- coronation_broken_oath_punishment_effect
Every has_game_rule = easy_difficulty in game/common and game/events, by the top-level object it sits in.
easy_difficulty
Very Easy
Disables achievements
You will be given significant bonuses, such as lessening the impact of disease, hostile schemes and stress. It will also be much easier to handle Factions.
Players get the modifier very_easy_difficulty (“Very Easy”):
- Health+1
- Disease Resistance (Health)+1
- Tyranny Gain-75%
- Fertility+20%
- Stress Gain-50%
- Short Reign Duration-50%
- Vassal Opinion+25
- Liege Opinion+50
- Enemy Hostile Scheme Phase Length40 days slower per Scheme Phase
The script checks it 19 times, in 16 places
Scripted modifiers (AI weights) 6
- ai_agent_join_chance_hostile_general_suite_modifier
- ai_agent_join_chance_hostile_title_modifier
- ai_agent_join_chance_personal_general_suite_modifier
- common_faction_modifiers
- hostile_scheme_base_chance_modifier
- hostile_scheme_title_base_chance_modifier
Script values 3
- disease_outbreak_pulse_chance_of_no_event
- hostile_scheme_base_odds_prediction_guts_value
- outbreak_chance_major_mult_value
Combat phase events 2
- commander_killed
- commander_none
Factions 2
- Escalated Peasant Faction
- Peasant Faction
Events 1
- … A Journey's End?
Character interactions 1
- Ask to Join my Movement
Scripted effects 1
- coronation_broken_oath_punishment_effect
Every has_game_rule = very_easy_difficulty in game/common and game/events, by the top-level object it sits in.
very_easy_difficulty

Source: game/common/game_rules/00_game_rules.txt line 1 (key difficulty), modifiers from game/common/modifiers, names from the English localisation; Crusader Kings III 1.20.1.2.