Ragnarok Zero will be published by Game321, a company that you may know from titles like: Wartune, Tales of Solaris, Pockie Ninja and others. The release date wasn't announced yet, but we know that they aim for a closed beta test at the end of 2013.
The game want to bring the world of Ragnarok Online to your browser, combining modern game features with one of the most nostalgic art styles known to gamers. As a lone adventurer, you will answer the call to protect the Kingdom of Prontera from demons, undead and other monstrosities that are gathering on the town borders. More details about classes and features will be available soon.
If you are interested in this project check Ragnarok Zero official page.