Fire is energetic. It burns hot. So giving people with fire-based abilities an equally fiery temperament acts as a kind of shorthand or shortcut, the same as giving them red hair or clothes. And then there's this trope.
This is one example of a Power Stereotype Flip (of which this is a Sub-Trope), giving characters with fiery powers (or lots of firepower — see Kill It with Fire, Mad Bomber and Throw Down The Bomblette) a more serene, stoic, composed, wise, or just plain nice personality that contrasts with the destructive power of fire. It's often justified In-Universe by explaining that they need to maintain their cool to keep their chosen element from getting out of control. It can be equally justified that it is one area where the normal choleric personality actually has the fire-forged patience (heh heh) to keep their cool.
Note that this differs from a character who is merely hiding their inner fire under a veneer of Tranquil Fury — these slow-burning characters also have a less restrained or outright sadistic personality (though the latter is sometimes still present as a "true self", a darker half or even a Super-Powered Evil Side which sometimes slips through). And despite being at odds with the more expected, passionate, Hot-Blooded portrayal of other firestarters, this can still be considered a Personality Power; the calm personality can represent the fire of hearth and hospitality or industry, with which flames and bonfires are symbolically linked, even while still dropping hints at the threat fire can still pose if left unchecked.
Particularly common with characters who harness The Power of the Sun rather than harsher earthly (or hellish) flames. Compare Genius Bruiser for another character archetype which contrasts with their usual portrayal, and Making a Splash, for characters who wield the element this personality is more commonly associated with. Contrast Pyromaniac and Burning with Anger.
- Fullmetal Alchemist:
- While Playing with Fire is the norm for Katekyō Hitman Reborn!, being how people's powers manifest in the setting, remaining completely calm while using them is considered an outstanding achievement. That state is called "Hyper Dying Will Mode". When protagonist Tsuna uses it, his personality does a complete 180, from an exaggeratedly emotional kid to calm and focused, hardly ever changing his tone or expression.
- Lyrical Nanoha:
- Signum has a natural affinity for the fire element (allowing her to convert her mana into flame at will) and includes flames in pretty much all of her combat spells. Personality-wise, she verges on Germanic Depressives levels of stoic. This is possibly justified by the elemental affinities like hers being just a random genetic trait among mages in the setting, rather than being tied to their personalities.
- Nanoha's Material counterpart Stern (who is even more stoic than Signum) gains fire powers in the second video game as well as all later appearances in other continuities. Even she isn't sure how it happened, though from a meta perspective it's probably so she'd have Lightning/Fire Juxtaposition with Fate's counterpart Levi.
- Played With in My Hero Academia with Shoto Todoroki. He speaks softly but tends to give others the cold shoulder, but he has both fire and ice powers. At first he avoids using his fire to spite his abusive fire-using father, but then has a Not So Stoic moment the first time he does break it out in combat. However, even when he does come to terms with his fire side, he still remains calm and collected.
- Sailor Mars in the Sailor Moon manga is a level-headed Shinto priestess with fire-related powers tied to the red planet (unless she gets mad). The anime makes her a more straightforward "hot-tempered" fire user.
- Naruto: The Uchiha clan is associated with fire jutsu. One of the first jutsu Sasuke learned was fire-based and he frequently uses fire jutsu. Sasuke is an unemotional and aloof person on default.
- K has Mikoto Suoh the Red King, who, despite his fire powers is incredibly stoic and laid-back.
- Child of the Storm:
- This is the ideal nature of a Phoenix host, as demonstrated by the White Phoenix of the Crown, Lily Potter. This is because Phoenix fire amplifies and is amplified by emotions, risking the host becoming Drunk on the Dark Side and Jumping Off the Slippery Slope very quickly if they're not careful. It's why they're very carefully picked, because when they're not, the result was Surtur, the original Dark Phoenix. And Harry, who's not a conventional host, but has a fragment of the Phoenix within him, ends up as a fledgling Dark Phoenix after a brutal Trauma Conga Line causes him to snap, before he's talked down through the Power of Love and the Power of Friendship.
- Harry quickly develops a gift for fire-magic, and has a fragment of the Phoenix inside him, which protected him from the Killing Curse, and while he's initially Hot-Blooded, he later develops it into Tranquil Fury, before progressing towards this during the second book to ensure that he doesn't become the Dark Phoenix again and learns how to control the Phoenix within him, becoming calmer, wiser, and more thoughtful. However, it should be noted that he does still have a temper.
- Young Charlie McGee from Stephen King's Firestarter, a child that can generate spontaneous combustion just by concentrating on the target. Once the sinister government agents kill her father, Charlie wants out of their facility. The Film of the Book shows actress Drew Barrymore as Charlie give the eye to every Shop agent she meets, giving each the chance to stand down. Alas, Shop agents are all Too Dumb to Live and dare to oppose Charlie, which nets them instant cremation right where they stand. Although the complex and all its personnel are left a roaring bonfire, it was not a Roaring Rampage of Revenge by a hothead; it was a methodical eradication of all those who opposed her, with Charlie's grim purpose being especially chilling.
- Gandalf from The Lord of the Rings bears Narya, the Red Ring of Fire, which may account for his skill with fireworks and flames in general (e.g. the wargs outside Moria). He's an archetypal wizard with all the calmness and wisdom that entails (although he does have a temper occasionally — subtle and quick to anger and all that: "Bilbo Baggins! Do not take me for some conjurer of cheap tricks!").
Gandalf: I am a servant of the Secret Fire, wielder of the flame of Anor. You cannot pass.
- Unlike his Fiery Redhead counterpart in the video games, Heat in Quantum Devil Saga: Avatar Tuner is calm and collected at all times, The Quiet One and he displays Dissonant Serenity at the creepiest moments. He only breaks out of this attitude when fighting.
- Melisandre from A Song of Ice and Fire, who predominantly uses fire-based magic, is cold, calculating, and composed.
- Hestia, the goddess of hearth and home in Classical Mythology, symbolizing the domestic warmth of the fireplace and the flames of the sacred pyres and braziers of the temple altars. Despite her Odd Job God status, she is Zeus' eldest sister, and was one of the Twelve Olympians. However, instead of killing/raping mortals like her siblings, she prefers peace and stays a virgin. She even gave up her seat among the Twelve Olympians to Dionysus to prevent conflict. One of the Orphic Hymns sung in her name:
Hestia . . . who dwellest amidst great fire's eternal flame; in sacred rites these ministers are thine, mystics much blessed, holy and divine. In thee the Gods have fixed their dwelling place, strong, stable basis of the mortal race.
- Digital Devil Saga
- Lupa is a very cool-headed tribe leader who even keeps a poker face through having a knife suddenly appear at the side of his throat. He also has the most potent fire attacks in the entire duology.
- Heat, the fire user of the team, enters a state of Tranquil Fury during Berserk mode.
- Heat O'Brien, the very deliberate basis for the guy above. In flashbacks he is depicted as having a very short temper that he barely managed to control. However, over the years he has become much more coolheaded and is very calm even when fighting his long-time Arch-Enemy. He is also a fire user.
- Fate Series
- In Fate/Apocrypha and the Fate/EXTRA series, Karna possesses the Mana Burst (Flames) skill, which allows him to light all of his weapons on fire with the sun's flames through his heritage to the sun god, Surya. Due to being abandoned at an early age, he has No Social Skills and rarely expresses what he's feeling on his face, which combined with his tendency for Brutal Honesty makes him appear resentful and bitter. In reality, he's a generous All-Loving Hero, which is why he is called the "Hero of Charity".
- Fate/Grand Order introduces Arjuna, who also possesses the Mana Burst (Flames) skill as well as a bow gifted to him by the god of fire himself. He tries to be an unflappable, cool-headed hero, but his burning jealousy for Karna and constant desire to prove himself makes his Blood Knight tendencies far more obvious.
- Brynhild from Fate/Prototype also possesses the Mana Burst (Flames) skill, and intentionally puts on the front of an Ice Queen. This is because she's afraid of opening herself up to others and especially her Master because if she does, there's always the risk she'll start to fall in love with them due to being reminded of her love, Sigurd. And the more she falls in love, the greater her compulsion to kill them becomes, usually by the end of her flaming spear.
- Tatsuya Suou from Persona 2 is this trope most of the time. While his Unique Personas are all focused on fire magic, he is depicted as an Ineffectual Loner with a hidden heart of gold. Justified in Innocent Sin where he is a Heroic Mime, but he maintains the attitude in Eternal Punishment with some notable exceptions.
- Yukiko from Persona 4 fits this trope to a tee (her main offensive element is fire and she's the demure daughter of the local innkeeper), right down to occasionally showing flashes of a much more brutal personality (most notable after scoring a critical hit). She's contrasted with Chie who similarly inverts the personality associated with An Ice Person.
- Blaze the Cat from the Sonic the Hedgehog series not only has fiery powers but is also a cold, aloof loner who keeps her emotions boiled up. Introverted or not, it's not a good idea to make her angry.
- Grillby from Undertale has a head that's Wreathed in Flames, but he's The Quiet One.
- Played with in Avatar: The Last Airbender.
- The page image is Uncle Iroh, a laidback, goofy Mentor Archetype who happens to be the Fire Lord's brother. Early in the series, he's mostly played as his nephew Zuko's comic relief, though rather than a case of Obfuscating Stupidity, he really believes that one of the best lessons his nephew could learn is how to lighten up. Iroh is deeply kind, very wise, and one of the most skilled firebenders in the world — though perhaps not necessarily as powerful as his brother, as firebending in particular is generally fuelled by strong emotion (though as it turns out, it doesn't have to be, the original method focusing much more on its association with life rather than rage and hatred, and he's considered to be the only person other than Aang who could conceivably beat Ozai in a straight fight).
- Many of the more prominent firebenders appear outwardly calm, but this is often a Mask of Sanity, one which Anti-Villain Zuko tries and often fails to maintain. Ozai, his daughter and dragon Azula, and Admiral Zhao all derive significant power from their reserves of Tranquil Fury, but have Hair-Trigger Tempers and eventually crumble when their various plans start to fall apart. A large part of Zuko's Character Development is about learning how to accept his anger and use it constructively, and let much of it go, rather than being controlled by it like his father and sister.
- Combustionbenders (who are able to focus heat into intense beams of pure destructive energy) are calm and reserved, as their specific powers require great focus. The Mysterious Mercenary Pursuer Sokka dubs "Combustion Man" is a Terminator expy who never speaks during his appearances.
- Then, in Sequel Series The Legend of Korra:
- Mako is a firebender who can lightningbend, a trait associated in the series with detachment, cool-headed discipline, and a waterbender-like sense of flow, and the responsible sibling to his brother, Bolin, a Nice Guy earthbender who eventually learns to lavabend, thus combining his happy-go-lucky attitude with another sort of fire. The most excitable member of the trio is Hot-Blooded Avatar Korra herself, born of the Water Tribe but a much straighter take on the usual Hot-Blooded firebender stereotype, to the point where it's her go-to element — her excitable and direct nature being the reason it takes her so long to master airbending.
- Downplayed with Season 3's P'li, Big Bad Zaheer's lover and second-in-command. She's another combustionbender, but while fairly self-serious in general, the bulk of her characterization shown is the deep mutual love between her and Zaheer, who "showed her what true freedom means."