The Dark Druid (災いを招く者 Wazawai wo maneku mono, called Basilisk Glance in the Japanese version) class is a class unique to Nergal, the main antagonist of Fire Emblem: Rekka no Ken. It is an extremely powerful class and can use all forms of Magic. In the class description it is implied that the “Dark Druid” class is promoted from the Druid class, though no character in the game is ever promoted in such a way.
The class description says: “A master druid whose heart is bound in darkness.”
Although Dark Druids are capable of using staves, they have no animation for it. This is because the only Dark Druid in the game, Nergal, doesn't use a staff, and the designers probably wanted to save a little time by not creating one.
The only weapon that Nergal has, Ereshkigal, is the only weapon intended for the Dark Druid. However, other weapons can be equipped; it just chops off a bit of the front of the sprite.
In the German version of the game, caused by a translation mistake, the class is called "Geomant", which means "Geomancer". Geomancy though is a form of telling the future and has nothing to with the Dark Druid. The correct translation would have been "Dunkler Druide".