Hello WillSuranol,
Before all, I am so sorry if this will not help you. This is just a burst of my mind, trying to give a suggestion for you.
I do not recommend you to use any kind of desktop environment on your Ragnarok Server because (for me) it will consume so much memory that are really valuable if they are given just to the server.
That is what on my mind. Therefore, I am suggesting you to study some basic Centos Codes that are needed to run a Ragnarok Server (I was a noob to. I used Ubuntu VPS, in spite of Windows, which needs much cost of both RAM and money). Otherwise, I feel that I succeeded, I was able to operate the server in.
Otherwise, If you are willing to use a Desktop environment for your Centos, I would suggest you to use "vnc-server". you can have them by doing
yum install vnc-server
on your PuTTy console.
This one may help you with the Desktop environment: http://www.host1free.com/forum/vps-technical-support/7990-how-install-remote-desktop-windows-7-centos-6-a.html
Have a nice day!