1. Log in to your account :
https://mangaart.jp/ja/login
2. Click "Membership Information"
https://mangaart.jp/account
3. Click "Delete Your Account" located toward the bottom of the page.
4. Please read all the information and be sure to check all the boxes.
5. Click "Delete Your Account" again.
6. A confirmation screen will appear showing you that your account deletion has been successful.