Fairy type weakness will need to be known if you want to do well in Pokémon Sword and Shield. While the Fairy type was introduced in Generation VI as GameFreaks introduced new Pokémon with the Fairy type, 22 Pokémon and three moves were changed to be of the Fairy type.
Pokémon Sword and Shield have more fairy-type Pokémon. So to defeat these type of Pokémon, you'll need specific counters.
Fairy Type Weakness: Which Pokémon Should You Use Against Fairy-Type Pokémon
If you want to fight fairy Pokémon, use need to use poison and steel-type Pokémon. Both do double damage against fairy Pokémon. Whatever you do, don't use dark, bug, or fighting-type Pokémon. All three do half damage against fairy with dark and fighting taking twice the damage against fairy. The best version to use is steel as poison is weak against psychic moves which are fairly common on fairy-type Pokémon.
Having a powerful steel-type Pokémon will win you the day and make for a much better adventure in Pokémon Sword and Shield.
Photo courtesy of GameFreaks