Fairy was introduced in Pokémon X and Y as the first new Pokémon type since Generation II.
The Fairy type debuted with the Generation VI games Pokémon X and Y in 2013. Its introduction expanded the type system to 18 types and added new strategic relationships, particularly involving Dragon, Fighting, Poison, and Steel Pokémon.
Several older Pokémon were also reclassified or given Fairy as an additional type. For example, Clefairy and Jigglypuff gained Fairy typing, while new Pokémon such as Sylveon were designed around the new category. This means Fairy was not limited to species newly created for Generation VI.
Generation II, represented by Pokémon Gold and Silver, had previously introduced Dark and Steel. No new type appeared in the core series between that generation and X and Y. Fairy is therefore different from later battle mechanics such as Mega Evolution, which was also introduced in Generation VI.