It made its first real appearance in Aiding the Enemy!, sleeping with Paul's other Pokémon.
Magmar was finally shown battling in Paul's match against Pyramid King Brandon in A Pyramiding Rage!. It was the first Pokémon chosen by Paul to battle him. He quickly recalled it after he saw Brandon chose Regirock to battle it. He sent it out again to battle Registeel but was soon called back. After all of Paul's other Pokémon were defeated, Paul sent out Magmar to battle Regirock again, where it was finally subdued.
Magmar's evolution was revealed in Pedal to the Mettle! when Paul chose Magmortar to battle Ash's Pikachu. They begun the battle in Evolving Strategies!, where Pikachu got badly burned because of Magmortar's Flame Body before Ash recalls it and sends out Buizel. Despite the type disadvantage, Magmortar was able to hold its own (in fact was only pushed back slightly from Ash's Buizel's Aqua Jet and Pikachu's Iron Tail) until it was recalled by Paul.
In DP184, Magmortar was used in the battle against Barry's Skarmory. It defeated Skarmory with a single Flamethrower. Then, Magmortar fought against Barry's Empoleon, where it was shown to be strong enough to withstand Empoleon's Hydro Cannon. It was then recalled by Paul.