Gandalf is now able to create a witch king!
To use in game, create Gandalf,then click on the Toggle Mounted button. It will create a witch king with low hitpoints.
To install, open your INI file and insert the file Gandalf.ini under the name "data\ini\object\goodfaction\units\men\gandalf.ini" (most of this will be provided for you!) and allow it to overwrite, then save.