Howdy, since I'm leaving C9 due to Webzen messing up completely, no support, 100 of bugs, DC issues, no fixes, bots, hackers, ddos attacks,......... I HAVE FINALLY enough. These are only some of sites I was using, but do check Japans blog sites (they are like 500+ of them) for C9, you find A LOT there.
First of, of course Japan C9 site:
http://c9.hangame.co.jp/
There are also Blog links, these are worth to read (not all), because it tells you latest rumors.
The most information WIKI for C9:
http://www.c9wiki.com/
Japan C9 "forum":
http://community.hangame.co.jp/
Subject: FYI, Sites of my sources 
Thu Dec 05, 2013 4:49 pm
