Ash's Charizard evolved from Charmander in the Pokémon TV series. Charmander is the Fire-type Pokémon that Ash receives after its original Trainer abandons it.
Ash's Charmander joins his team after Ash and his friends rescue it from dangerous weather and learn that it has been waiting for its Trainer to return. It later evolves into Charmeleon and then Charizard. The final evolution creates a recurring challenge because Charizard is powerful but initially refuses to obey Ash.
Charmander is one of the three original Kanto starter Pokémon, alongside Bulbasaur and Squirtle. It evolves into Charmeleon at level 16 and Charizard at level 36 in the video games, although the anime does not present evolution as a strict level-based process. Ash's Charizard eventually develops strong loyalty toward him.