find_nth_from_last

# File activerecord/lib/active_record/relation/finder_methods.rb, line 608
      def find_nth_from_last(index)
        if loaded?
          records[-index]
        else
          relation = ordered_relation

          if relation.order_values.empty? || relation.has_limit_or_offset?
            relation.records[-index]
          else
            relation.reverse_order.offset(index - 1).first
          end
        end
      end