Square Enix opened the official LINE account of the Dragon Quest of the Stars smartphone game in Japan. You can add it using the QR code in the gallery and you will get all the latest information directly from your LINE messenger.
It should be noted that you can download the free Dragon Quest of the Stars LINE sticker set after you added the account but sadly, the set is available only from Japan (you can add the account from all regions). The sticker will be available in your LINE after the download for 180 days. You can download it until June 12, 2017.