diff --git a/app/models/faction.rb b/app/models/faction.rb
index 7a2d75c8..de5a7912 100644
--- a/app/models/faction.rb
+++ b/app/models/faction.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-# TODO(plural): add a side code to faction.
 class Faction < ApplicationRecord
+  belongs_to :side
   has_many :cards
 end
diff --git a/app/models/side.rb b/app/models/side.rb
index e160c981..936da615 100644
--- a/app/models/side.rb
+++ b/app/models/side.rb
@@ -2,4 +2,5 @@
 
 class Side < ApplicationRecord
   has_many :cards
+  has_many :factions
 end
diff --git a/db/schema.rb b/db/schema.rb
index d5b07fb2..237f84f9 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -81,6 +81,7 @@
   create_table "factions", id: :string, force: :cascade do |t|
     t.boolean "is_mini", null: false
     t.text "name", null: false
+    t.text "side_id", null: false
     t.datetime "created_at", precision: 6, null: false
     t.datetime "updated_at", precision: 6, null: false
   end
@@ -118,6 +119,7 @@
   add_foreign_key "cards", "card_types", column: "card_type_id", primary_key: "id"
   add_foreign_key "cards", "factions", column: "faction_id", primary_key: "id"
   add_foreign_key "cards", "sides", column: "side_id", primary_key: "id"
+  add_foreign_key "factions", "sides", column: "side_id", primary_key: "id"
   add_foreign_key "printings", "cards", column: "card_id", primary_key: "id"
   add_foreign_key "printings", "card_sets", column: "card_set_id", primary_key: "id"
 end
diff --git a/lib/tasks/cards.rake b/lib/tasks/cards.rake
index 6c8eae7f..68b7ef16 100644
--- a/lib/tasks/cards.rake
+++ b/lib/tasks/cards.rake
@@ -68,6 +68,7 @@ namespace :cards do
     factions.map! do |f|
       {
         id: f['code'],
+        side_id: f['side_code'],
         name: f['name'],
         is_mini: f['is_mini']
       }