this is good.. please include special features like PvP and WoE... just announce when will be the official release of the server and the website to see this.

and to answer your question if this is legal or Not. The answer is legal, as long as based on Aethena, it is an opensource and licensed thru GNU, thanks.

http://www.trap17.com/index.php/Private-Server-Ro_t38129.html