You can use a HEX editor to change names. Basically you make a name like "Kapiikulu", open up your character's information in the HEX editor, highlight "ii" and replace the HEX for those two letters with the HEX for "ı", save, and launch up cRPG. Nevertheless, you will get kicked immediately, because special characters aren't allowed on the servers.
Supposedly there were issues with kicking players from servers if they had a name with special characters, but I've heard they have long since been patched in Native.
If you go to the Víkingr mod, you will see many names with special characters like ð þ æ ö and so on.