diff --git a/app/models/weapon_stat_modifier.rb b/app/models/weapon_stat_modifier.rb
new file mode 100644
index 0000000..91fa115
--- /dev/null
+++ b/app/models/weapon_stat_modifier.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+##
+# Reference table for weapon stat modifiers (AX skills and befoulments).
+#
+# AX skills are positive modifiers that can be applied to certain weapons.
+# Befoulments are negative modifiers that appear on Odiant weapons.
+#
+class WeaponStatModifier < ApplicationRecord
+  CATEGORIES = %w[ax befoulment].freeze
+
+  validates :slug, presence: true, uniqueness: true
+  validates :name_en, presence: true
+  validates :category, presence: true, inclusion: { in: CATEGORIES }
+  validates :polarity, inclusion: { in: [-1, 1] }
+
+  scope :ax_skills, -> { where(category: 'ax') }
+  scope :befoulments, -> { where(category: 'befoulment') }
+
+  def self.find_by_game_skill_id(id)
+    find_by(game_skill_id: id.to_i)
+  end
+
+  def buff?
+    polarity == 1
+  end
+
+  def debuff?
+    polarity == -1
+  end
+end
diff --git a/db/data/20251230000001_seed_weapon_stat_modifiers.rb b/db/data/20251230000001_seed_weapon_stat_modifiers.rb
new file mode 100644
index 0000000..507b023
--- /dev/null
+++ b/db/data/20251230000001_seed_weapon_stat_modifiers.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+class SeedWeaponStatModifiers < ActiveRecord::Migration[8.0]
+  def up
+    ax_skills = [
+      # Primary AX Skills
+      { slug: 'ax_hp', name_en: 'HP', name_jp: 'HP', category: 'ax', stat: 'hp', polarity: 1, suffix: '%', base_min: 1, base_max: 11, game_skill_id: 1588 },
+      { slug: 'ax_atk', name_en: 'ATK', name_jp: '攻撃', category: 'ax', stat: 'atk', polarity: 1, suffix: '%', base_min: 1, base_max: 3.5, game_skill_id: 1589 },
+      { slug: 'ax_def', name_en: 'DEF', name_jp: '防御', category: 'ax', stat: 'def', polarity: 1, suffix: '%', base_min: 1, base_max: 8, game_skill_id: 1590 },
+      { slug: 'ax_ca_dmg', name_en: 'C.A. DMG', name_jp: '奥義ダメ', category: 'ax', stat: 'ca_dmg', polarity: 1, suffix: '%', base_min: 2, base_max: 8.5, game_skill_id: 1591 },
+      { slug: 'ax_multiattack', name_en: 'Multiattack Rate', name_jp: '連撃率', category: 'ax', stat: 'multiattack', polarity: 1, suffix: '%', base_min: 1, base_max: 4, game_skill_id: 1592 },
+
+      # Secondary AX Skills
+      { slug: 'ax_debuff_res', name_en: 'Debuff Resistance', name_jp: '弱体耐性', category: 'ax', stat: 'debuff_res', polarity: 1, suffix: '%', base_min: 1, base_max: 3, game_skill_id: 1593 },
+      { slug: 'ax_ele_atk', name_en: 'Elemental ATK', name_jp: '全属性攻撃力', category: 'ax', stat: 'ele_atk', polarity: 1, suffix: '%', base_min: 1, base_max: 5, game_skill_id: 1594 },
+      { slug: 'ax_healing', name_en: 'Healing', name_jp: '回復性能', category: 'ax', stat: 'healing', polarity: 1, suffix: '%', base_min: 2, base_max: 5, game_skill_id: 1595 },
+      { slug: 'ax_da', name_en: 'Double Attack Rate', name_jp: 'DA確率', category: 'ax', stat: 'da', polarity: 1, suffix: '%', base_min: 1, base_max: 2, game_skill_id: 1596 },
+      { slug: 'ax_ta', name_en: 'Triple Attack Rate', name_jp: 'TA確率', category: 'ax', stat: 'ta', polarity: 1, suffix: '%', base_min: 1, base_max: 2, game_skill_id: 1597 },
+      { slug: 'ax_ca_cap', name_en: 'C.A. DMG Cap', name_jp: '奥義上限', category: 'ax', stat: 'ca_cap', polarity: 1, suffix: '%', base_min: 1, base_max: 2, game_skill_id: 1599 },
+      { slug: 'ax_stamina', name_en: 'Stamina', name_jp: '渾身', category: 'ax', stat: 'stamina', polarity: 1, suffix: nil, base_min: 1, base_max: 3, game_skill_id: 1600 },
+      { slug: 'ax_enmity', name_en: 'Enmity', name_jp: '背水', category: 'ax', stat: 'enmity', polarity: 1, suffix: nil, base_min: 1, base_max: 3, game_skill_id: 1601 },
+
+      # Extended AX Skills (axType 2)
+      { slug: 'ax_skill_supp', name_en: 'Supplemental Skill DMG', name_jp: 'アビ与ダメ上昇', category: 'ax', stat: 'skill_supp', polarity: 1, suffix: nil, base_min: 1, base_max: 5, game_skill_id: 1719 },
+      { slug: 'ax_ca_supp', name_en: 'Supplemental C.A. DMG', name_jp: '奥義与ダメ上昇', category: 'ax', stat: 'ca_supp', polarity: 1, suffix: nil, base_min: 1, base_max: 5, game_skill_id: 1720 },
+      { slug: 'ax_ele_dmg_red', name_en: 'Elemental DMG Reduction', name_jp: '属性ダメ軽減', category: 'ax', stat: 'ele_dmg_red', polarity: 1, suffix: '%', base_min: 1, base_max: 5, game_skill_id: 1721 },
+      { slug: 'ax_na_cap', name_en: 'Normal ATK DMG Cap', name_jp: '通常ダメ上限', category: 'ax', stat: 'na_cap', polarity: 1, suffix: '%', base_min: 0.5, base_max: 1.5, game_skill_id: 1722 },
+
+      # Utility AX Skills (axType 3)
+      { slug: 'ax_exp', name_en: 'EXP Gain', name_jp: 'EXP UP', category: 'ax', stat: 'exp', polarity: 1, suffix: '%', base_min: 5, base_max: 10, game_skill_id: 1837 },
+      { slug: 'ax_rupie', name_en: 'Rupie Gain', name_jp: '獲得ルピ', category: 'ax', stat: 'rupie', polarity: 1, suffix: '%', base_min: 10, base_max: 20, game_skill_id: 1838 }
+    ]
+
+    befoulments = [
+      { slug: 'befoul_atk_down', name_en: 'ATK Down', name_jp: '攻撃力DOWN', category: 'befoulment', stat: 'atk', polarity: -1, suffix: '%', base_min: -12, base_max: -6, game_skill_id: nil },
+      { slug: 'befoul_def_down', name_en: 'DEF Down', name_jp: '防御力DOWN', category: 'befoulment', stat: 'def', polarity: -1, suffix: '%', base_min: -25, base_max: -21, game_skill_id: 2880 },
+      { slug: 'befoul_da_ta_down', name_en: 'DA/TA Down', name_jp: '連撃率DOWN', category: 'befoulment', stat: 'da_ta', polarity: -1, suffix: '%', base_min: -22, base_max: -19, game_skill_id: nil },
+      { slug: 'befoul_ca_dmg_down', name_en: 'CA DMG Down', name_jp: '奥義ダメージDOWN', category: 'befoulment', stat: 'ca_dmg', polarity: -1, suffix: '%', base_min: -38, base_max: -26, game_skill_id: nil },
+      { slug: 'befoul_dot', name_en: 'Damage Over Time', name_jp: '毎ターンダメージ', category: 'befoulment', stat: 'dot', polarity: -1, suffix: '%', base_min: 6, base_max: 16, game_skill_id: nil },
+      { slug: 'befoul_hp_down', name_en: 'Max HP Down', name_jp: '最大HP減少', category: 'befoulment', stat: 'hp', polarity: -1, suffix: '%', base_min: -50, base_max: -26, game_skill_id: nil },
+      { slug: 'befoul_debuff_down', name_en: 'Debuff Success Down', name_jp: '弱体成功率DOWN', category: 'befoulment', stat: 'debuff_success', polarity: -1, suffix: '%', base_min: -16, base_max: -6, game_skill_id: nil },
+      { slug: 'befoul_ability_dmg_down', name_en: 'Ability DMG Down', name_jp: 'アビリティダメージDOWN', category: 'befoulment', stat: 'ability_dmg', polarity: -1, suffix: '%', base_min: -50, base_max: -50, game_skill_id: nil }
+    ]
+
+    now = Time.current
+    (ax_skills + befoulments).each do |attrs|
+      WeaponStatModifier.create!(attrs.merge(created_at: now, updated_at: now))
+    end
+  end
+
+  def down
+    WeaponStatModifier.delete_all
+  end
+end
diff --git a/db/migrate/20251230000001_create_weapon_stat_modifiers.rb b/db/migrate/20251230000001_create_weapon_stat_modifiers.rb
new file mode 100644
index 0000000..750a733
--- /dev/null
+++ b/db/migrate/20251230000001_create_weapon_stat_modifiers.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class CreateWeaponStatModifiers < ActiveRecord::Migration[8.0]
+  def change
+    create_table :weapon_stat_modifiers do |t|
+      t.string :slug, null: false
+      t.string :name_en, null: false
+      t.string :name_jp
+      t.string :category, null: false
+      t.string :stat
+      t.integer :polarity, default: 1, null: false
+      t.string :suffix
+      t.float :base_min
+      t.float :base_max
+      t.integer :game_skill_id
+
+      t.timestamps
+    end
+
+    add_index :weapon_stat_modifiers, :slug, unique: true
+    add_index :weapon_stat_modifiers, :game_skill_id, unique: true
+    add_index :weapon_stat_modifiers, :category
+  end
+end