Jin is a 13 year old boy with dark gray fur, and purple eyes. He wears black pants, and dark blue shoes with 1 spike on the back of each.
Where his brother Nero is hot-tempered and quick to draw first punch, Jin is cold, aloof, and borderline sociopathic. He cares little for the feelings of others, and denounces, in his own words, trivialities like camaraderie, believing that such things are lies that people use to their advantage. He has no compunction with killing anyone who gets in the way of his goal.
This, however, is all a façade. The moment he reunites with Nero, Jin loses his calm, detached demeanor and reverts to his childhood self. His voice becomes noticeably more ecstatic, and he is now prone to fits of maniacal laughter. Jin is a cold and calculating individual, completely dedicated in his one desire to kill Nero that his own life didn't matter to him.
According to Eggman, Jin alone is shouldering nothing but overwhelming and accumulating hatred. After Eggman told Jin that Nero is the reincarnation of a being of there clan that terrorized it, and destroyed it, Jin vowed revenge against Nero, wishing to wipe out the Nero to destroy all remains of the being. At first, Jin was at least unwilling to kill those unrelated to revenge plot, but over time as his hatred increased, such convictions were dropped, becoming cruel and ruthless.
Jin is able to manipulate fire, and is a master at it. He can create, shape and manipulate fire, the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products, flame being the visible portion of the fire. Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity will be different. Create/Generate/increase, absorb, shape and manipulate fire. Burn/melt, Ultimate Burning, Incineration, Fire Attacks, Flame Solidification. Pyrokinetic Constructs, including weapons, walls, armor or allies/servants. He can surround himself in fire becoming hot to the touch. He is an extreme danger to others. He can achieve flight by lifting himself by the fire surrounding him, or by propelling himself.
He is also a master of manipulating magma. With Magma he can create, shape and manipulate molten rock (magma while underground, lava when on surface), a mixture of molten or semi-molten rock, volatiles and solids, it may also contain suspended crystals, dissolved gas and gas bubbles. Create/generate/increase molten stone. Shape, compress, and/or otherwise manipulate molten stone.Eruption Inducement to rise volcanoes and/or cause eruptions. Geo-Thermokinetic Constructs, including weapons, walls, armor or allies/servants. Heat Absorption, Heat Generation varying from painful burns to combustion. Magma Attacks.
Unnatural senses, even by animal standards
Tail can sense danger.
Jin is an amazing swordsman, comparable to his brother Nero. Jin was a swordsman of great skill. In life, his swordsmanship skills resembled a mix of Japanese style Kenjutsu and Battojutsu. His skill with the sword was so great that he was capable of slicing through steel, and also easily defeated Nero in there first battle, a first-rate swordsman, and a dragon (the latter of which made him a legend) with little effort. Jin was also a very fast runner with high endurance, capable of jumping from great heights (as shown by his landing after slaying the dragon in mid-air); these skills allowed him to sustain no injuries after his battle in Monsters. He was renowned as the strongest swordsman of his time.
Jin Fights with an elegant samurai sword and sheath style using quick slashes.
Not very trusting
Heat Haze: Jin shoots a stream of fire from the palm of his hand.
Blaze Fist: Jin turns his fist into flames and launches it as a column of fire at his target. This attack is so incredibly powerful that it is able to plow through several ships in one shot.
Fire Pistols: Pointing the index and middle fingers of both hands at an opponent like guns, Jin turns his fingertips into flames and shoots bullets made of fire from them.
Flame Commandment: Jin amasses a large amount of flames around his body (usually by first swinging his outstretched hand around him, summoning the flames) in preparation for an attack.
Fire Pillar: Used following Flame Commandment. Jin shoots the collected flames straight upward, destroying a target above him. It can also be fired downwards to clear any enemies that might be below him while he's in mid-air.
St. Elmo's Flare: Jin hurls long lances made out of fire. The lances have the combined effect of simultaneously burning an opponent while piercing them.
Great Flame Commandment: Flame Emperor: Jin's ultimate fire technique. After creating great spiraling flames centered on his location before amassing it at a focused point (i.e. the palm of his hand), Ace then turns it into a gigantic fireball resembling the sun and hurls it at his opponent to try to obliterate them.
Great Eruption: Jin transforms his fists into pure lava before throwing it forward, like an over-sized rocket. The explosion causes volcanic rock to hit the ground, in a method similar to meteors.
Volcano's Meteor: Jin creates a great number of magma fists that he fires into the air in order to let them rain down upon the battlefield, causing enormous amounts of area damage. This looks like a cross between a meteor shower and a volcanic eruption.
Hound Blaze: Jin creates a wave of magma, shaped like a wolf's head.
Dark Dog: Jin transforms his hand into magma and lashes out at the opponent with a claw-thrust.
Volcano Explosion: Jin transforms his hand into magma, and then punches the ground. This results in an eruption of volcanic rocks around the punch area and several spots around it, inflicting damage to anyone within the blast radius.