The Unova Starter Pokémon can be picked out of three Pokémon that cannot be found in the Unova Region. The three starter Pokémon are: Snivy a grass-type Pokémon, Oshawott a water-type Pokémon and Tepig a fire type Pokémon. These have the abilities: Overgrow that will increase the Pokémon grass moves when the Pokémon has only 30% of its HP left, Torrent that will increase the Pokémon water moves when the Pokémon has only 30% of its HP left and Blaze that will increase the Pokémon fire type moves when the Pokémon has only 30% of its HP left.
In Pokémon Black Version and Pokémon White Version, Professor Juniper brings the Pokémon to the player's house, after which Cheren and Bianca come and pick up their starter Pokémon along with the player. Cheren will pick up a Pokémon that is strong against the player's Pokémon, while Bianca picks up the Pokémon that is weak against it.
In Pokémon Black Version 2 and Pokémon White Version 2, Bianca is coming to the starting town Aspertia City to give the player his/her new starter Pokémon. Unfortunately the player's rival Hugh doesn't get a new starter Pokémon but will battle you with the Pokémon that he got since it was an egg. He has a Pokémon that is stronger than your starter Pokémon.