diff --git a/app/controllers/api/v1/api_controller.rb b/app/controllers/api/v1/api_controller.rb
index 73c51a1..087b455 100644
--- a/app/controllers/api/v1/api_controller.rb
+++ b/app/controllers/api/v1/api_controller.rb
@@ -20,6 +20,7 @@ module Api
       rescue_from Api::V1::FavoriteAlreadyExistsError, with: :render_unprocessable_entity_response
       rescue_from Api::V1::NoJobProvidedError, with: :render_unprocessable_entity_response
       rescue_from Api::V1::TooManySkillsOfTypeError, with: :render_unprocessable_entity_response
+      rescue_from Api::V1::IncompatibleWeaponForPositionError, with: :render_unprocessable_entity_response
       rescue_from Api::V1::UnauthorizedError, with: :render_unauthorized_response
       rescue_from ActionController::ParameterMissing, with: :render_unprocessable_entity_response
 
diff --git a/app/controllers/api/v1/grid_weapons_controller.rb b/app/controllers/api/v1/grid_weapons_controller.rb
index a6324bd..8ecb573 100644
--- a/app/controllers/api/v1/grid_weapons_controller.rb
+++ b/app/controllers/api/v1/grid_weapons_controller.rb
@@ -6,11 +6,45 @@ module Api
       before_action :set, except: %w[create update_uncap_level destroy]
 
       def create
+        # BUG: I can create grid weapons even when I'm not logged in on an authenticated party
         party = Party.find(weapon_params[:party_id])
-        canonical_weapon = Weapon.find(weapon_params[:weapon_id])
-
         render_unauthorized_response if current_user && (party.user != current_user)
 
+        incoming_weapon = Weapon.find(weapon_params[:weapon_id])
+        incoming_weapon.limit
+
+        # Set up conflict_position in case it is used
+        conflict_position = nil
+
+        if [9, 10, 11].include?(weapon_params[:position].to_i) && ![11, 16, 17, 28, 29].include?(incoming_weapon.series)
+          raise Api::V1::IncompatibleWeaponForPositionError.new(weapon: incoming_weapon)
+        end
+
+        # 1. If the weapon has a limit
+        # 2. If the weapon does not match a weapon already in grid
+        # 3. If the incoming weapon has a limit and other weapons of the same series are in grid
+        if incoming_weapon.limit && incoming_weapon.limit.positive?
+          conflict_weapon = party.weapons.find do |weapon|
+            weapon if incoming_weapon.series == weapon.weapon.series ||
+                      ([2, 3].include?(incoming_weapon.series) && [2, 3].include?(weapon.weapon.series))
+          end
+
+          if conflict_weapon
+            if conflict_weapon.weapon.id != incoming_weapon.id
+              return render json: ConflictBlueprint.render(nil, view: :weapons,
+                                                                conflict_weapons: [conflict_weapon],
+                                                                incoming_weapon: incoming_weapon,
+                                                                incoming_position: weapon_params[:position])
+            else
+              # Destroy the original grid weapon
+              # TODO: Use conflict_position to alert the client that that position has changed
+              conflict_position = conflict_weapon.position
+              GridWeapon.destroy(conflict_weapon.id)
+            end
+          end
+        end
+
+        # Destroy the existing item before adding a new one
         if (grid_weapon = GridWeapon.where(
           party_id: party.id,
           position: weapon_params[:position]
@@ -18,14 +52,44 @@ module Api
           GridWeapon.destroy(grid_weapon.id)
         end
 
-        weapon = GridWeapon.create!(weapon_params.merge(party_id: party.id, weapon_id: canonical_weapon.id))
+        weapon = GridWeapon.new
+        weapon.attributes = weapon_params.merge(party_id: party.id, weapon_id: incoming_weapon.id)
 
         if weapon.position == -1
           party.element = weapon.weapon.element
           party.save!
         end
 
-        render json: GridWeaponBlueprint.render(weapon, view: :full), status: :created if weapon.save!
+        # Render the new weapon and any weapons changed
+        return unless weapon.save!
+
+        render json: GridWeaponBlueprint.render(weapon, view: :full,
+                                                        root: :grid_weapon,
+                                                        meta: {
+                                                          replaced: conflict_position
+                                                        }),
+               status: :created
+      end
+
+      def resolve
+        incoming = Weapon.find(resolve_params[:incoming])
+        conflicting = resolve_params[:conflicting].map { |id| GridWeapon.find(id) }
+        party = conflicting.first.party
+
+        # Destroy each conflicting weapon
+        conflicting.each { |weapon| GridWeapon.destroy(weapon.id) }
+
+        # Destroy the weapon at the desired position if it exists
+        existing_weapon = GridWeapon.where(party: party.id, position: resolve_params[:position]).first
+        GridWeapon.destroy(existing_weapon.id) if existing_weapon
+
+        uncap_level = 3
+        uncap_level = 4 if incoming.flb
+        uncap_level = 5 if incoming.ulb
+
+        weapon = GridWeapon.create!(party_id: party.id, weapon_id: incoming.id,
+                                    position: resolve_params[:position], uncap_level: uncap_level)
+        render json: GridWeaponBlueprint.render(weapon, view: :nested), status: :created if weapon.save!
       end
 
       def update
@@ -71,6 +135,10 @@ module Api
           :awakening_type, :awakening_level
         )
       end
+
+      def resolve_params
+        params.require(:resolve).permit(:position, :incoming, conflicting: [])
+      end
     end
   end
 end
diff --git a/app/controllers/api/v1/search_controller.rb b/app/controllers/api/v1/search_controller.rb
index e317c96..9792109 100644
--- a/app/controllers/api/v1/search_controller.rb
+++ b/app/controllers/api/v1/search_controller.rb
@@ -57,6 +57,7 @@ module Api
               filters['proficiency1']
           end
           conditions[:series] = filters['series'] unless filters['series'].blank? || filters['series'].empty?
+          conditions[:extra] = filters['extra'] unless filters['extra'].blank?
         end
 
         weapons = if search_params[:query].present? && search_params[:query].length >= 2
@@ -89,6 +90,7 @@ module Api
         if filters
           conditions[:rarity] = filters['rarity'] unless filters['rarity'].blank? || filters['rarity'].empty?
           conditions[:element] = filters['element'] unless filters['element'].blank? || filters['element'].empty?
+          conditions[:subaura] = filters['subaura'] unless filters['subaura'].blank?
         end
 
         summons = if search_params[:query].present? && search_params[:query].length >= 2
diff --git a/app/errors/api/v1/incompatible_weapon_for_position_error.rb b/app/errors/api/v1/incompatible_weapon_for_position_error.rb
new file mode 100644
index 0000000..48ab067
--- /dev/null
+++ b/app/errors/api/v1/incompatible_weapon_for_position_error.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module Api
+  module V1
+    class IncompatibleWeaponForPositionError < GranblueError
+      def http_status
+        422
+      end
+
+      def code
+        'incompatible_weapon_for_position'
+      end
+
+      def message
+        'A weapon of this series cannot be added to Additional Weapons'
+      end
+
+      def to_hash
+        {
+          message: message,
+          code: code,
+          weapon: @data[:weapon]
+        }
+      end
+    end
+  end
+end
diff --git a/config/routes.rb b/config/routes.rb
index de3e5f7..91094d7 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -41,6 +41,7 @@ Rails.application.routes.draw do
       delete 'characters', to: 'grid_characters#destroy'
 
       post 'weapons', to: 'grid_weapons#create'
+      post 'weapons/resolve', to: 'grid_weapons#resolve'
       post 'weapons/update_uncap', to: 'grid_weapons#update_uncap_level'
       delete 'weapons', to: 'grid_weapons#destroy'