The fraction of damage a Dark type move will deal is shown - ½ means damage (not very effective), means 2 (super-effective) and so on. Which types of Pokemon attacks are effective against which types of Pokemon? Dark Type Good against : Ghost, Psychic Bad against : Fighting, Dark Steel.
Dragon Type Good against : Dragon Bad against : Ice, Steel. Electric Type Good against : Water. Introduced in Generation VI, the Fairy type is super effective against Dark and not resisted by Ghost.
Asked in Pokemon X and Y What is the Fairy-type super effective against ? Below are the differences compared to the current type chart. The charts can be seen on the Old Type Charts page. There was no Fairy type. Ghost and Dark type moves were not very effective against Steel type Pokémon. From Generation they do neutral damage.
The Dark-type (あくタイプ Aku taipu in Japanese) is one of the eighteen Pokémon elemental types. Type Chart methods of representing Type effectiveness have been popular since long before Pokémon Go, with all of the core Pokémon games revolving around them. In brief, Pokémon types dictate.

