He was fully introduced in BW002: Enter Iris and Axew, where he was the first Pokémon that Ash scanned with his new Pokédex, although he was aiming it at Iris' hair and so wondered why it looked nothing like the Pokédex image. Axew struck up a fast friendship with Ash's Pikachu, showing that he is very friendly. Axew is shown to have a close bond with Iris, as she tried everything to rescue him from a Sandile's mouth in BW003: A Sandile Gusher of Change.
According to Cilan in BW005: Triple Leaders, Team Threats, Axew and Iris have perfect compatibility. He later watched Ash's battle against the three Leaders of the Striaton Gym. In BW006: Dreams by the Yard Full!, it is revealed that Axew's dream is to evolve into a Haxorus.
Axew has some childish traits about it, as shown in BW008: Saving Darmanitan From the Bell!, where he starting fighting with Pikachu because he thought Pikachu had stolen his food. It is shown in BW009: The Bloom Is on Axew! that Axew is a weak battler, as he cries even when hit by weak attacks. Despite this, he has a powerful attack, Dragon Rage. However, he hasn't quite mastered it yet, so when he uses it, the attack accidentally explodes everywhere instead of being fired at an opponent, which Ash and Cilan teasingly call "Dragon Sneeze", much to the annoyance of Iris. It is also revealed that Iris obtained Axew from a matriarch in her hometown (Dragon Village, as stated in The Bloom is on Axew) when he was a baby.
After being told that he will be like a "big brother" to the Pokémon inside Ash's egg, Axew began dancing happily and accidentally knocked the egg down a hill. It was saved by Pikachu before any harm could come to it. After seeing how aggressive Scraggy was, Axew kept his eye on it and was the first to realize when he had wandered off. After Scraggy was paralysed by a Galvantula, Axew helped Iris find a plant that would cure him. Axew battled Scraggy the following day, with the battle ending in a draw. They had a second battle in BW020, but it ended after Axew attempted to use Dragon Rage.
In The Club Battle Finale: A Heroes Outcome! Iris used her Axew against Luke's Golett at the Don George Tournament and during the battle Axew learned the move Outrage which helped Axew win the battle.