The official Client is up here, the only thing it does is a download manager for the full client:

http://playragnarokrestart.com/Download/GameDownload

You can get the download manager here if the above does not work:

http://mirror.irowiki.org/ragnarok/fullclient/RagnarokRestart-DLM.exe
MD5: f444276f9d7dabf859e990e0559f9ba4

Mirror for the client install: http://mirror.irowiki.org/ragnarok/fullclient/RagnarokRestartInstaller.zip
Torrent: http://mirror.irowiki.org/ragnarok/fullclient/RagnarokRestartInstaller.zip.torrent
Google drive: https://drive.google.com/open?id=0B5JBFeTwylUGX1hwOVJQbk44ajg
SPLIT FILES: http://mirror.irowiki.org/ragnarok/fullclient/installer_split/
(you will need 7zip, get it here)
MD5: da49d84b3ffe6acfa5b6092580a9b4e9

Mirror for the zipped client install: http://mirror.irowiki.org/ragnarok/fullclient/RESTART.zip
Torrent: http://mirror.irowiki.org/ragnarok/fullclient/RESTART.zip.torrent
Google drive: https://drive.google.com/open?id=0B5JBFeTwylUGWU5GUkRMWUNSZEU
SPLIT FILES: http://mirror.irowiki.org/ragnarok/fullclient/zippedclient_split/
(you will need 7zip, get it here)
MD5: 01ccac3a2926d2126361a97d8094754c

If you are experiencing the “Side by Side” error when attempting to load the game, download the following C++ runtimes. They should resolve the issue.
Side by side error fix: http://mirror.irowiki.org/ragnarok/fullclient/vcredist/