diff --git a/app/services/dataminer.rb b/app/services/dataminer.rb
new file mode 100644
index 0000000..c63528b
--- /dev/null
+++ b/app/services/dataminer.rb
@@ -0,0 +1,251 @@
+# frozen_string_literal: true
+
+class Dataminer
+  include HTTParty
+
+  BOT_UID = '39094985'
+  GAME_VERSION = '1741068713'
+
+  base_uri 'https://game.granbluefantasy.jp'
+  format :json
+
+  HEADERS = {
+    'Accept' => 'application/json, text/javascript, */*; q=0.01',
+    'Accept-Language' => 'en-US,en;q=0.9',
+    'Accept-Encoding' => 'gzip, deflate, br, zstd',
+    'Content-Type' => 'application/json',
+    'DNT' => '1',
+    'Origin' => 'https://game.granbluefantasy.jp',
+    'Referer' => 'https://game.granbluefantasy.jp/',
+    'User-Agent' => 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36',
+    'X-Requested-With' => 'XMLHttpRequest'
+  }.freeze
+
+  attr_reader :page, :cookies, :logger, :debug
+
+  def initialize(page:, access_token:, wing:, midship:, t: 'dummy', debug: false)
+    @page = page
+    @cookies = {
+      access_gbtk: access_token,
+      wing: wing,
+      t: t,
+      midship: midship
+    }
+    @debug = debug
+    setup_logger
+  end
+
+  def fetch
+    timestamp = Time.now.to_i * 1000
+    response = self.class.post(
+      "/#{page}?_=#{timestamp}&t=#{timestamp}&uid=#{BOT_UID}",
+      headers: HEADERS.merge(
+        'Cookie' => format_cookies,
+        'X-VERSION' => GAME_VERSION
+      )
+    )
+
+    raise AuthenticationError if auth_failed?(response)
+
+    response
+  end
+
+  def fetch_character(granblue_id)
+    timestamp = Time.now.to_i * 1000
+    url = "/archive/npc_detail?_=#{timestamp}&t=#{timestamp}&uid=#{BOT_UID}"
+    body = {
+      special_token: nil,
+      user_id: BOT_UID,
+      kind_name: '0',
+      attribute: '0',
+      event_id: nil,
+      story_id: nil,
+      style: 1,
+      character_id: granblue_id
+    }
+
+    response = fetch_detail(url, body)
+    update_game_data('Character', granblue_id, response) if response
+    response
+  end
+
+  def fetch_weapon(granblue_id)
+    timestamp = Time.now.to_i * 1000
+    url = "/archive/weapon_detail?_=#{timestamp}&t=#{timestamp}&uid=#{BOT_UID}"
+    body = {
+      special_token: nil,
+      user_id: BOT_UID,
+      kind_name: '0',
+      attribute: '0',
+      event_id: nil,
+      story_id: nil,
+      weapon_id: granblue_id
+    }
+
+    response = fetch_detail(url, body)
+    update_game_data('Weapon', granblue_id, response) if response
+    response
+  end
+
+  def fetch_summon(granblue_id)
+    timestamp = Time.now.to_i * 1000
+    url = "/archive/summon_detail?_=#{timestamp}&t=#{timestamp}&uid=#{BOT_UID}"
+    body = {
+      special_token: nil,
+      user_id: BOT_UID,
+      kind_name: '0',
+      attribute: '0',
+      event_id: nil,
+      story_id: nil,
+      summon_id: granblue_id
+    }
+
+    response = fetch_detail(url, body)
+    update_game_data('Summon', granblue_id, response) if response
+    response
+  end
+
+  # Public batch processing methods
+  def fetch_all_characters(only_missing: false)
+    process_all_records('Character', only_missing: only_missing)
+  end
+
+  def fetch_all_weapons(only_missing: false)
+    process_all_records('Weapon', only_missing: only_missing)
+  end
+
+  def fetch_all_summons(only_missing: false)
+    process_all_records('Summon', only_missing: only_missing)
+  end
+
+  private
+
+  def format_cookies
+    cookies.map { |k, v| "#{k}=#{v}" }.join('; ')
+  end
+
+  def auth_failed?(response)
+    return true if response.code != 200
+
+    begin
+      parsed = JSON.parse(response.body)
+      parsed.is_a?(Hash) && parsed['auth_status'] == 'require_auth'
+    rescue JSON::ParserError
+      true
+    end
+  end
+
+  def setup_logger
+    @logger = ::Logger.new($stdout)
+    @logger.level = debug ? ::Logger::DEBUG : ::Logger::INFO
+    @logger.formatter = proc do |severity, _datetime, _progname, msg|
+      case severity
+      when 'DEBUG'
+        debug ? "#{msg}\n" : ''
+      else
+        "#{msg}\n"
+      end
+    end
+
+    # Suppress SQL logs in non-debug mode
+    return if debug
+
+    ActiveRecord::Base.logger.level = ::Logger::INFO if defined?(ActiveRecord::Base)
+  end
+
+  def fetch_detail(url, body)
+    logger.debug "\n=== Request Details ==="
+    logger.debug "URL: #{url}"
+    logger.debug 'Headers:'
+    logger.debug HEADERS.merge(
+      'Cookie' => format_cookies,
+      'X-VERSION' => GAME_VERSION
+    ).inspect
+    logger.debug 'Body:'
+    logger.debug body.to_json
+    logger.debug '===================='
+
+    response = self.class.post(
+      url,
+      headers: HEADERS.merge(
+        'Cookie' => format_cookies,
+        'X-VERSION' => GAME_VERSION
+      ),
+      body: body.to_json
+    )
+
+    logger.debug "\n=== Response Details ==="
+    logger.debug "Response code: #{response.code}"
+    logger.debug 'Response headers:'
+    logger.debug response.headers.inspect
+    logger.debug 'Raw response body:'
+    logger.debug response.body.inspect
+    begin
+      logger.debug 'Parsed response body (if JSON):'
+      logger.debug JSON.parse(response.body).inspect
+    rescue JSON::ParserError => e
+      logger.debug "Could not parse as JSON: #{e.message}"
+    end
+    logger.debug '======================'
+
+    raise AuthenticationError if auth_failed?(response)
+
+    JSON.parse(response.body)
+  end
+
+  def update_game_data(model_name, granblue_id, response_data)
+    return unless response_data.is_a?(Hash)
+
+    model = Object.const_get(model_name)
+    record = model.find_by(granblue_id: granblue_id)
+
+    if record
+      record.update(game_raw_en: response_data)
+      logger.debug "Updated #{model_name} #{granblue_id}"
+    else
+      logger.warn "#{model_name} with granblue_id #{granblue_id} not found in database"
+    end
+  rescue StandardError => e
+    logger.error "Error updating #{model_name} #{granblue_id}: #{e.message}"
+  end
+
+  def process_all_records(model_name, only_missing: false)
+    model = Object.const_get(model_name)
+    scope = model
+    scope = scope.where(game_raw_en: nil) if only_missing
+
+    total = scope.count
+    success_count = 0
+    error_count = 0
+
+    logger.info "Starting to fetch #{total} #{model_name.downcase}s#{' (missing data only)' if only_missing}..."
+
+    scope.find_each do |record|
+      logger.info "\nProcessing #{model_name} #{record.granblue_id} (#{success_count + error_count + 1}/#{total})"
+
+      response = case model_name
+                 when 'Character'
+                   fetch_character(record.granblue_id)
+                 when 'Weapon'
+                   fetch_weapon(record.granblue_id)
+                 when 'Summon'
+                   fetch_summon(record.granblue_id)
+                 end
+
+      success_count += 1
+      logger.debug "Successfully processed #{model_name} #{record.granblue_id}"
+
+      sleep(1)
+    rescue StandardError => e
+      error_count += 1
+      logger.error "Error processing #{model_name} #{record.granblue_id}: #{e.message}"
+    end
+
+    logger.info "\nProcessing complete!"
+    logger.info "Total: #{total}"
+    logger.info "Successful: #{success_count}"
+    logger.info "Failed: #{error_count}"
+  end
+
+  class AuthenticationError < StandardError; end
+end