DS-012 Creating a Guild is impossible because of the Guild name.

To create a Guild, you need to go see the NPC "Hero Shangguan" in the city of "Lunaria." You must be at least level 20, not already in a Guild, and pay 500,000 silver coins. Then you need to enter the Guild name and choose an icon. When I enter the name, it says:

Guild name includes illegal content!

I've tried several names without success: Fusion, fusion, abcde, Caesar, ...