You can add your very own wizard to Shadow Magic using the advanced editor. Doing this will allow you to choose a custom portrait, any "avatar" you would want to use, and even come up with custom messages for wizard to use when negotiating.
The steps are pretty simple...
Use the ILB editor (ILed) which is included in the game to import your custom portraits to a custom ILB.
Then go into the advanced editor, go to the wizard section, add a new entry using the ILB you created for the face and portrait sections. From here, you can also choose any avatar to represent your new custom wizard, you can also give the wizard his/her sphere selection, name, stats, abilities, default color and default race. And just for flavor, don't forget to give your wizard some witty things to say when he/she breaks alliances, declares war etc.
When you are done, not only will you have a new wizard to play that can be chosen at the wizard select screen, This wizard can also be played against as a new opponent Remember, you want to add your new wizard to the Resource, Library and Face section to make it fully functional just like the default wizards. Hope this helps some people make their custom wizard dreams come true, I know it is not very detailed, but I too lazy to write up anything terribly detailed.