Darmanitan is an extremely strong, prideful, confident, and smug Pokémon. It is shown to take great pride in the fact that it is a Fire-type Pokémon, and that it can perform powerful Fire-type moves. Darmanitan was also shown to bully weaker Pokémon that can't perform certain moves, specifically Scorbunny, due to the fact that it didn't know any Fire-type moves despite being a Fire-type Pokémon. Despite having a confident exterior, it has been shown to coward out when it feels outnumbered, such as when it fled in fear from the group of Bug types lead by Goh's Scyther, despite having the type-advantage, and later hid behind Goh's Sandile when it was tricked into believing Sandile was stronger than it was. Darmanitan respects Pokémon that it acknowledges as being strong, such as Ash's Dragonite and Goh's Scyther, and is obedient to Goh's commands.
Darmanitan was originally one of the Zen Mode Darmanitan living outside the Desert Resort's ruins. It was woken up by Pikachu and Scorbunny and tried to attack them, only to be captured by Goh afterwards. It was then used in a battle alongside Ash's Dragonite against a giant Golurk, which Darmanitan defeated by using Overheat. After a while, it was shown in its Zen Mode, where it was sleeping with his former foe.
Later, at Cerise Park, Darmanitan belittled and provoked Goh's Scorbunny, mockingly laughing after witnessing it struggling to use Ember.
During the food shortage at Cerise Park, Darmanitan led a group of miscellaneous Pokémon as they fought against the Bug-type Pokémon group lead by Goh's Beedrill. When Goh's Scyther took control of the group, It and its group fled in fear of being beaten. Darmanitan later joined forces with Goh's other Pokémon to protect Goh's Cascoon as they evolved into Dustox after Goh's Golurk lost control and caused a flood with its Rain Dance.
When Goh's Pokémon were playing a ball game, it bullied Goh's Sobble by scaring the latter. When Sobble was practicing Water Gun, Darmanitan bullied it again and was happy that Sobble could not retaliate. The next day, Darmanitan was sleeping under a tree when it was suddenly splashed by water from above, which angered it, though it was unaware that it was Sobble who did so.
- Darmanitan's capture marks the first time a main character has captured a Pokémon with its Hidden Ability.
- Darmanitan is also Goh's first Pokémon to activate its Ability, as well as the first one to have his Ability confirmed.
At the Cerise Laboratory