diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index 6877c70..b6e7d5d 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -110,7 +110,8 @@ class PostsController < ApplicationController
     original_created_before = params[:original_created_before]
 
     post = Post.find(params[:id].to_i)
-    tags = post.tags.where(category: 'nico').to_a + Tag.normalise_tags(tag_names)
+    tags = post.tags.where(category: 'nico').to_a +
+           Tag.normalise_tags(tag_names, with_tagme: false)
     if post.update(title:, tags:, original_created_from:, original_created_before:)
       render json: post.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }),
              status: :ok
diff --git a/backend/app/controllers/users_controller.rb b/backend/app/controllers/users_controller.rb
index 8658a5f..4ee4836 100644
--- a/backend/app/controllers/users_controller.rb
+++ b/backend/app/controllers/users_controller.rb
@@ -6,12 +6,15 @@ class UsersController < ApplicationController
   end
 
   def verify
+    ip_bin = IPAddr.new(request.remote_ip).hton
+    ip_address = IpAddress.find_or_create_by!(ip_address: ip_bin)
+
     user = User.find_by(inheritance_code: params[:code])
-    render json: if user
-                   { valid: true, user: user.slice(:id, :name, :inheritance_code, :role) }
-                 else
-                   { valid: false }
-                 end
+    return render json: { valid: false } unless user
+
+    UserIp.find_or_create_by!(user:, ip_address:)
+
+    render json: { valid: true, user: user.slice(:id, :name, :inheritance_code, :role) }
   end
 
   def renew
diff --git a/backend/app/models/tag.rb b/backend/app/models/tag.rb
index 137afff..e80baff 100644
--- a/backend/app/models/tag.rb
+++ b/backend/app/models/tag.rb
@@ -57,7 +57,7 @@ class Tag < ApplicationRecord
         end
       end
     end
-    tags << Tag.tagme if with_tagme && tags.size < 20 && tags.none?(Tag.tagme)
+    tags << Tag.tagme if with_tagme && tags.size < 10 && tags.none?(Tag.tagme)
     tags.uniq
   end
 
diff --git a/backend/app/models/user.rb b/backend/app/models/user.rb
index 830d383..ede464a 100644
--- a/backend/app/models/user.rb
+++ b/backend/app/models/user.rb
@@ -8,7 +8,6 @@ class User < ApplicationRecord
 
   has_many :posts
   has_many :settings
-  has_many :ip_addresses
   has_many :user_ips, dependent: :destroy
   has_many :ip_addresses, through: :user_ips
   has_many :user_post_views, dependent: :destroy
diff --git a/backend/db/migrate/20251126231500_rename_ip_adress_column_to_ip_addresses.rb b/backend/db/migrate/20251126231500_rename_ip_adress_column_to_ip_addresses.rb
new file mode 100644
index 0000000..60f78e6
--- /dev/null
+++ b/backend/db/migrate/20251126231500_rename_ip_adress_column_to_ip_addresses.rb
@@ -0,0 +1,5 @@
+class RenameIpAdressColumnToIpAddresses < ActiveRecord::Migration[8.0]
+  def change
+    rename_column :ip_addresses, :ip_adress, :ip_address
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index 4d5cfd6..b8210d8 100644
--- a/backend/db/schema.rb
+++ b/backend/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
+ActiveRecord::Schema[8.0].define(version: 2025_11_26_231500) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -40,7 +40,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
   end
 
   create_table "ip_addresses", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.binary "ip_adress", limit: 16, null: false
+    t.binary "ip_address", limit: 16, null: false
     t.boolean "banned", default: false, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
@@ -70,9 +70,16 @@ ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
     t.bigint "deleted_user_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.datetime "discarded_at"
+    t.virtual "is_active", type: :boolean, as: "(`discarded_at` is null)", stored: true
+    t.virtual "active_unique_key", type: :string, as: "(case when (`discarded_at` is null) then concat(`post_id`,_utf8mb4':',`tag_id`) else NULL end)", stored: true
+    t.index ["active_unique_key"], name: "idx_post_tags_active_unique", unique: true
     t.index ["created_user_id"], name: "index_post_tags_on_created_user_id"
     t.index ["deleted_user_id"], name: "index_post_tags_on_deleted_user_id"
+    t.index ["discarded_at"], name: "index_post_tags_on_discarded_at"
+    t.index ["post_id", "discarded_at"], name: "index_post_tags_on_post_id_and_discarded_at"
     t.index ["post_id"], name: "index_post_tags_on_post_id"
+    t.index ["tag_id", "discarded_at"], name: "index_post_tags_on_tag_id_and_discarded_at"
     t.index ["tag_id"], name: "index_post_tags_on_tag_id"
   end
 
@@ -107,6 +114,15 @@ ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
     t.index ["tag_id"], name: "index_tag_aliases_on_tag_id"
   end
 
+  create_table "tag_implications", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "tag_id", null: false
+    t.bigint "parent_tag_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["parent_tag_id"], name: "index_tag_implications_on_parent_tag_id"
+    t.index ["tag_id"], name: "index_tag_implications_on_tag_id"
+  end
+
   create_table "tag_similarities", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "tag_id", null: false
     t.bigint "target_tag_id", null: false
@@ -176,6 +192,8 @@ ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
   add_foreign_key "posts", "users", column: "uploaded_user_id"
   add_foreign_key "settings", "users"
   add_foreign_key "tag_aliases", "tags"
+  add_foreign_key "tag_implications", "tags"
+  add_foreign_key "tag_implications", "tags", column: "parent_tag_id"
   add_foreign_key "tag_similarities", "tags"
   add_foreign_key "tag_similarities", "tags", column: "target_tag_id"
   add_foreign_key "user_ips", "ip_addresses"
diff --git a/backend/lib/tasks/link_nico.rake b/backend/lib/tasks/link_nico.rake
deleted file mode 100644
index 0c02f48..0000000
--- a/backend/lib/tasks/link_nico.rake
+++ /dev/null
@@ -1,12 +0,0 @@
-namespace :nico do
-  desc 'ニコタグ連携'
-  task link: :environment do
-    Post.find_each do |post|
-      tags = post.tags.where(category: 'nico')
-      tags.each do |tag|
-        post.tags.concat(tag.linked_tags) if tag.linked_tags.present?
-      end
-      post.tags = post.tags.to_a.uniq
-    end
-  end
-end
diff --git a/backend/lib/tasks/sync_nico.rake b/backend/lib/tasks/sync_nico.rake
index a8601c5..9fe28fb 100644
--- a/backend/lib/tasks/sync_nico.rake
+++ b/backend/lib/tasks/sync_nico.rake
@@ -51,7 +51,7 @@ namespace :nico do
             end
             tags_to_add.concat([tag] + tag.linked_tags)
           end
-          tags_to_add << Tag.tagme if post.tags.size < 20
+          tags_to_add << Tag.tagme if post.tags.size < 10
           tags_to_add << Tag.bot
           post.tags = (post.tags + tags_to_add).uniq
         end