Cheren is a childhood friend of the player who also lives in the starting town of Nuvema Town. As he holds a greater degree of knowledge about Pokémon than his friends and tends to offer the player advice during the course of their journey, his comments are often witty and intellectual. He also misunderstands Bianca's humor often, to her dismay. While Professor Juniper describes him as being very honest, she also remarks that he can be 'a little difficult'; his impatience in particular is often seen throughout the earlier stages of his journey. He is also described as being quite judgmental by Alder.
In keeping with the theme of truth and ideals often seen in Black and White, Cheren represents those who pursue ideals—more precisely, as N pointed out in Chargestone Cave, the ideal of strength. His goal is to become the Champion and he always strives to become stronger. However, when Alder asked him for the first time why he strives to become stronger, he was quite unsure of his reasons. He then starts to ponder to himself how to do so—something that Alder said he used to do with his partner Pokémon as well—and what exactly it means to be strong. Alder also remarked that Cheren is a lot like Marshal.
Like the player and Bianca, Cheren receives a starter Pokémon as a gift from Professor Juniper at the start of the game. He always chooses the starter with a type advantage over the player's starter. The player will encounter and battle him several times throughout the game. After the main storyline, Cheren can be found on Route 5. After talking to him there, he moves to Victory Road, where he can be battled once a day.
Cheren appears numerous times throughout the game, such as in Driftveil and Opelucid City, as well as Route 21. He gives the player and Hugh advice and guidance on the current situation, such as the freezing of Opelucid City, where Drayden learns of Cheren's ascension to the position of Aspertia Gym Leader.