Wizard

From DwarfFortressWiki

A wizard is a fanciful person who is merely the stuff of legends. They do not actually exist, appearing only in engravings as the fancy of artists, as there is no such thing as magic. All dwarves know this, and anyone who says otherwise is surely an elven trickster.

[edit] In the future

Wizards are a placeholder for the magic system. Dwarf Fortress presently does not include a magic system, so they are in the game's raw object data only in order to allow them to appear in engravings. In the future, wizardry will likely be a skill, and wizards would probably then be represented in art in some other fashion.