Gajeel is a tall and muscular young man with light-tan skin and long, spiky black hair, which is usually kept slicked back, revealing his forehead. He has red eyes with slitted dark pupils, and has no visible eyebrows. Most of his exposed body is covered in sets of simple, round studs. The most visible studs are on his face, with three of them above each of his eyes (acting as "eyebrows" of sorts), three on each side of his nose, and two on his chin, just below his mouth. His ears are adorned by two sets of five earrings each. After gaining Future Saito's Dragon Skin magic, he now has his son's blue, rune-like tattoos across his arms, chest, shoulders and torso.
He also sports four studs on each of his forearms, with his right one being covered in scars. His black Fairy Tail mark is located on his left arm, just below his shoulder. Being a Dragon Slayer, Gajeel's canine teeth are distinctively sharper than normal.
Gajeel's attire consists primarily of a dark blue trench coat, whose tail reaching down to his upper-calves, with a dark flame pattern across the coat's hemline and silver-grey edges. Underneath is a green, short-sleeved shirt that has light- and dark-colored patterns on the front and collar, along with loose, beige pants, with a grey belt around his waist, and a pair of black, studded boots that tucks his pants in. His hair remains the same, albeit with strands of hair on the side of his head, hiding his ears, and wearing a dark yellow bandanna on his forehead. He also wears fingerless, dark brown gloves, with numerous studs on the knuckles.
Iron Dragon Slayer Magic: Gajeel was taught how to use Iron Dragon Slayer Magic by Metalicana, The Iron Dragon. As its name implies, Gajeel's particular Dragon Slayer Magic deals with the manipulation of iron. Gajeel eats iron to regain his own strength, and his teeth and jaw muscles are powerful enough to gnaw through solid metal with ease, even allowing him to eat the Magic-canceling metal of the Dorma Anim. Gajeel's Magic deals with producing multi-sized iron rods, as well as changing parts of his body into steel. Most of his attacks involve transforming his arms into blunt, metallic weapons, which he can do at will. Additionally, Gajeel may turn his iron into steel if he somehow becomes able to absorb trace amounts of carbon; said process is still toxic and harmful to his body as it would be to others, but the addition of the natural element changes the composition of his spells, allowing him to deal enhanced damage and/or break through defenses that his iron could not. His mastery of Iron Dragon Slayer Magic and becoming one of Fairy Tail's strongest S-Class Mage Candidates, has earned him the epithet "Black Steel (Japanese translation for Iron Dragon) Gajeel".
- Iron Dragon's Roar: Gajeel's exclusive, metal-based Dragon's Roar. After gathering Magic Power in his mouth, Gajeel shapes it into a powerful tornado which he subsequently emits and sends towards his foes. Such tornado possesses immense force, being capable of generating powerful explosions and inflicting heavy blunt damage, but also releases sharp shards of metal in the process, shredding the opponents' body.
- Iron Dragon's Club: Gajeel transforms his arm or leg into a large steel club, increasing his punching and kicking power. He can also create multiple, smaller clubs from the end of the original, hitting many enemies at once. The clubs can be elongated at Gajeel's will, making them powerful ranged weapons. He is also apparently capable of increasing their size dramatically and to detach them from his body: several of these clubs, enlarged to gargantuan size, were the main cause of the original Fairy Tail Building's destruction. Also, for added maneuverability and to take opponents off-guard, the club can be rapidly turned into the similar Iron Dragon's Sword.
- Iron Dragon's Sword: Gajeel transforms his arm or leg into a large, jagged steel blade, similarly to Iron Dragon's Club, but, rather than blunt power, this spell has cutting power, thereby making it deadlier. The spikes along the blade's edge make its slashes more painful and dangerous, and the weapon's length can be increased to reach enemies who are far away from Gajeel. The blade is also sturdy enough to function as a shield of sorts, as well as a chainsaw, effectively increasing its damage.
- Iron Dragon's Scales: Gajeel covers part of his body (or the entirety of it) in steel scales, dramatically increasing his offensive and defensive abilities. When punching and kicking while covered in these scales, Gajeel is capable of creating powerful gusts of wind through mere kinetic force. When confronted with Natsu Dragneel's flames, the resulting clash generated a powerful shock wave which heavily damaged the area surrounding the two of them. These scales are strong enough to shatter bone and rock alike, are resilient against regular flames, and much harder than normal iron, as shown when Panther Lily's Bustermarm Sword wasn't able to cut through them.
- Iron Dragon's Lance: Demon Logs: Gajeel extends one of his arms towards his turns his target's direction, with his fingers outstretched, turning it into a large spearhead, from which a large number of steel spears are fired towards his target in rapid succession.
- Iron Dragon's Foot Blade: Gajeel sprouts a sharp, harpoon-like blade from the sole of each of his feet. By planting these blades in the ceiling, he's capable of remaining suspended and to move around as if he were walking normally.
- Iron Dragon's Hard Fist: Gajeel punches the target while covered in Iron Dragon's Scales, greatly enhancing his punching power that could shatter both rock, metal, and bones alike.
- Dragon Slayer's Secret Art:
- Karma Demon: Iron God Sword: Seemingly one of his most, if not the most powerful spell in Gajeel's possession, being acknowledged as one of the Secret Arts attainable by the Iron Dragon Slayer. Gajeel claps his hands together above his head, creating a gigantic iron sword. He then proceeds to swipe the sword down, destroying a substantially large area in front of him.
Iron Shadow Dragon Mode: After eating Rogue Cheney's shadows, Gajeel gained the ability to use his Iron Dragon Slayer Magic enhanced with shadows. Gajeel can, also, turn his body into a shadow, granting him intangibility. Furthermore, as a shadow, Gajeel is unimpeded by things that would otherwise slow his physical body down, such as being in a large body of water. It greatly enhances his physical abilities as well, granting him enormous speed, monstrous strength and greater resilience towards attacks.
- Iron Shadow Dragon's Roar: Gajeel's alternate, shadow-enhanced version of his Iron Dragon's Roar. Gajeel quickly gathers and releases a large amount of iron and shadows from his mouth, generating a very large, powerful, destructive blast that can be seen throughout an area at least the size of Crocus.
- Iron Shadow Dragon's Club: Gajeel attacks his target with a shadow-cloaked Iron Dragon's Club. The damage dealt is increased by the addition of the swirling shadows.
- Iron Shadow Dragon's Sword: Gajeel gathers shadows and iron around his arms, creating a menacing jagged swords of iron, coated by shadows. Unlike his regular Iron Dragon's Sword, Gajeel is capable of making the blade become intangible, thus passing any defenses and going straight for the kill without any delay. Along with that, Iron Shadow Dragon's Sword has boasts greater cutting power, and can extend in a mere instant, and like it's iron counterpart, mass produce itself on Gajeel's body.
- Dragon Skin: Living Weapon:
- Immense Strength:
- Immense Durability:
- Enhanced Speed:
- Enhanced Iron Dragon Slayer Magic:
- Enhanced Iron Shadow Dragon Slayer Mode:
- Dragon's Spike:
Master Hand-to-Hand Combatant: In battle, aside from his Iron Dragon Slayer Magic, Gajeel is known for extensively employing unarmed combat, and to possess great proficiency in doing so. His style is a brutal one; consisting of powerful, direct moves such as devastating punches and headbutts, complemented by his high physical ability, with his strength making his blows highly damaging, and his speed allowing him to land them in extremely fast succession. When employed alongside his Iron Dragon's Scales, his unarmed blows become far deadlier. During his battle with Panther Lily, he was shown able to engage in midair confrontations, reaching the flying Exceed with a leap and then bombarding him with a barrage of punches, and his clash with Rogue Cheney during the Grand Magic Games proved him able to block and even counter-attack assaults from behind without the need to turn his back.
Immense Strength: Gajeel has shown, on different occasions to be quite strong, boasting strength that is unparalleled to normal humans, and considered downright monstrous: during his time under Jose Porla, while he was tormenting the captured Lucy Heartfilia, Gajeel casually head-butted a fellow Phantom Lord member with enough force to crack the stone floor the man crashed upon. His physical might is enough for him to clash with Natsu on even terms, to block and shatter Panther Lily's gargantuan Bustermarm Sword, and to pin down and hold still the gigantic Dorma Anim all by himself, allowing Natsu to finish it off. He's also capable of performing very high leaps, as shown from him reaching Panther Lily, who was floating in midair because of his Aera, from the ground, which was located several meters below him. Furthermore, he was capable of delivering several powerful blows to Rogue Cheney while blocking his Shadow Dragon Slayer Magic-enhanced attacks bare-handed.
Enhanced Durability: Even without his Dragon Slayer abilities, Gajeel has consistently proven himself to be a very resilient man: when he was confronted by Shadow Gear after joining Fairy Tail, he was able to shrug off the combined attacks from Jet and Droy without retaliation and only resorted to covering his body in his metal scales to protect Levy from Laxus' lightning. Also, during his battle with Laxus, he took an attack which would have, otherwise, killed Natsu and remained conscious. During his time in Edolas, Gajeel used his metal scales to fight Faust's mechanical Dragon, where he took extremely powerful hits and continued to fight.
Enhanced Smell: Gajeel has an incredible sense of smell, which he shares with other Dragon Slayers. He uses this for tracking purposes as apparently, nothing can escape his nose, best seen when he tracked down Lucy, who had escaped from Jose's imprisonment. It is also heavily implied that Gajeel used this skill to track down Levy, who ran away from him during the S-Class Trials out of frustration. He is also capable of identifying different scents, including blood, and tell whether it's fresh or not. Even if blinded, or in complete darkness, Gajeel can use his sense of smell in order to locate his foe, recognizing their scent, and differentiating it from other scents, finding his opponent, and managing to fight even if blinded.
Enhanced Speed: Gajeel's overall speed and reflexes are impressive, enough for him to intercept attacks like Laxus' Lightning Bolts and reach Levy in time to save her from an ambush consisting of two Grimoire Heart Mages. He is even capable of easily avoiding attacks, and immediately countering, as well as dodge any attacks before he could find an opening.
Immense Magic Power: Even though he was a former S-Class Mage back at the Phantom Lord Guild, Gajeel still boasts an immense amount of magic power equal to that of an average S-Class Mage. His level of magic energy easily makes him one of the strongest S-Class Mage Candidates of his guild. His magic color is deep grey with a shade of green to it.