Agro

Agro was the last major villain in the show. Originally, Gaines' son, Agro spent multiple years in a rocket ship, enclosed in a chamber filled with Sacred Water from ____ Lake/Pond. He is the most powerful villain in the show and is only the second major villain that is not a Descendant.

Background
Agro is the son of Gaines and is sent off in a rocket ship, to return multiple years later in order to wreak havoc on the world.

Agro is a living weapon and is mostly evil, with only a scrap of the good that was once in Agro as a child. Gaines' hatred toward all Descendants eventually made its way into Agro.

Forms
Agro takes many forms during his battles with the protagonists in the Agro Arc. Each evolution he goes through increases his size dramatically, excluding his Ultimate Form, where his height is nearly reduced by half and his weight is reduced by nearly a fifth.

Alpha Stage
Strength In Numbers: In Agro's Alpha Stage, he consists of 50 smaller versions of himself, that all act independently, though they all share the same personality. None of them are that powerful individually, but they can swarm and be a nuisance.

Flight: Agro is able to fly in all stages, ranging from simple levitation to full fledged flight. Flight allows Agro to flee from a scene quickly, as well as give him an aerial advantage in battle.

Proficient Hand to Hand Combatant: In the Alpha Stage, Agro fights with punches and kicks. He has no control of energy and lacks his signature abilities. Though small, Agro in the Alpha Stage can still deliver a blow with a significant amount of force.

Beta Stage
Strength In Numbers: In Agro's Beta Stage, he consists of 3 smaller versions of himself, that all act independently, with slightly different personalities. After assuming his Beta Stage, through the fusion of all parts of him in the Alpha Stage, he has become far more powerful, and much larger. Though there are only three of him now, they can still coordinate and provide problems for their opponents.

Enhanced Strength: After assuming his Beta Stage, Agro's strength has increased by many times. Punches and Kicks deal tremendous damage and can incpacitate opponents. He has the strength to crush rocks or trees.

Enhanced Stamina: In his Beta Stage, Agro has a large pool of stamina. It will run out, but he assumes his Final Stage before that happens.

Adequate Durability: In his Beta Stage, Agro has become far more durable. As opposed to the Alpha Stage, where he would blow up in wake of a powerful attack, he can now take much more damage and come out okay.

Enhanced Tolerance to Pain: This ablility ranges among the pieces of Agro in the Beta Stage. The Wicked Piece feels no pain and relishes in his blood. The Focused Piece feels pain, but can control himself. The Kind Piece does not enjoy the fighting and fights significantly less than the other two pieces. He is scared of pain and actively avoids that situation.

Healing Factor: In his Beta Stage, Agro can regenerate faster than the average man, but not at the level of absurdity.

Enhanced Perception: This ability also differs between the three pieces. The Wicked Piece is not very perceptive and can fall into traps that should have been seen through. The Focused Piece is far more intelligent, not falling for traps and tricks and simply trying to accomplish his goal. The Kind Piece has great perceptive skills, better than even the Focused Piece, but he fails to take advantage of it in battle.

Proficient Hand to Hand Combatant: Though much larger than before, Agro in the Beta Stage has skill in fighting. In addition to raw power, he has deceptive speed and agility.

Final Stage
Enhanced Strength: Gon has great strength as he, Kurapika, and Leorio cooperate could open the first door of the testing gate which was 2 tons in weight before learning Nen. He can also shatter rock and incapacitate skilled warriors by sending them flying with just a push of his hand. It is unknown how much he can press after learning Nen. However, as his aura spiked he managed to defeat Nobunaga in arm wrestling. He was also capable of punching a Chimera Ant several miles in the direction of another country.

Enhanced Stamina: Gon is indefatigable. He can withstand wearing battles, training sessions and runs.

Enhanced Durability: Primarily due to his being an Enhancer, Gon has a sturdier body than normal: an instance of it is given when Meleoron commented on how Hollow's feathers dealt him no damage at all.

Enhanced Tolerance to Pain: Gon has shown to be somewhat impervious to pain. This is mostly due to his obstinacy and determination more than to a physical predisposition. He could take having his arms being blown off by the Bomber and severed by Neferpitou, continuing to fight and winning nonetheless.

Healing Factor: Gon heals extremely quickly. It is not only thanks to his being an Enhancer, since there have been instances of it happening even before he learned Nen, such as when Hanzo broke his arm. Injuries that should take months to recover from disappear in a matter of weeks. This is true for poisons and toxins as well, as seen when Geretta paralyzed him during the Hunter Exam: according to him, Gon should have been unable to move for ten days, whereas Hisoka believed that four would suffice; however, Gon stood back up soon after the poison had ef fect.

Enhanced Perception: Gon managed to detect Meleoron's presence in spite of the latter specializing in erasing it.

Proficient Hand to Hand Combatant: Although he lacks both experience and technique, Gon has shown some skill in close quarter combat, as shown in his fights against Hisoka. He seems to be naturally talented, as he never trained in it, but learned from various clashes. His fighting style is unrefined but very versatile. He mainly resorts to his fists to strike, but can deliver powerful kicks as well.

Ultimate Form
Flight: Agro is able to fly in all stages, ranging from simple levitation to full fledged flight. Flight allows Agro to flee from a scene quickly, as well as give him an aerial advantage in battle.

Disciple's Eyes: A trait only assumed in his Uiltimate Form, Agro has many enhanced perceptive and strategic skills.
 * Enhanced Senses: With the Disciple's Eyes, Agro can see at nearly 360 degrees. In addition, he has an increased sense of smell and hearing. These enhanced senses allow Agro to see the world as if it were in slow-motion for most opponents.
 * Enhanced Perception: It is nearly impossible to hide from Agro's eyes. As well as 360 degree vision, he also has borderline x-ray vision and can see through some surfaces.
 * Excellent Strategist: Stemming from his enhanced senses, Agro is able to see the battlefield and perform the correct move in each situation in a similar way to how Plinio does with his Symbol Power.
 * Proficient Combatant: Also stemming from the enhanced senses, Agro is able to fight extremely efficiently, hitting his opponent's weak and vulnerable spots.
 * Enhances Reflexes: Another beneficiary from the enhanced senses, Agro now has sufficient speed to match his reflexes. After seeing the opponent's attack, he is able to react quickly and counter or block the attack.
 * Technique Copying: Agro's eyes allow him to copy any technique he sees used. Because his natural powers are superior to all other characters, his new version of that technique will likely be more potent.
 * Energy Copying: In addition to copying techniques, Agro can also copy different energy disciplines and replicate them, while using them simultaneously. The only thing he cannot copy are Symbol Powers.

Enhanced Strength: Though his size has decreased dramatically, his strength has increased many times over. His punches can split mountains and destroy buildings.

Enhanced Speed: The increase in speed in the Ultimate Form is one of the largest enhancements. In his Ultimate Form, Agro is the single fastest character in the show. At full speed he is invisible to the naked eye.

Enhanced Agility: In his Ultimate Form, Agro is extremely agile. His agility is so fast that he appears to teleport. He can stop on a dime.

Enhanced Stamina: Other than Leo who literally has infinite stamina, Agro has the most stamina in the show. In a way, because of his unique regeneration technique, he too can have infinite stamina.

Supreme Durability: Agro's Ultimate Form body is nearly impenetrable. He can take multiple powerful attacks without blocking and receive nothing more than dust buildup.

Enhanced Tolerance to Pain: It is unclear whether or not he actually feels pain or whether he is reacting to damage that may have a weakening effect on him.

Supreme Healing Factor: One of Agro's Ultimate Form signature abilities is his healing. His normal healing factor is accelerated and he can regenerate from damage very quickly. But if he accumulates a large amount of damage, he is able to regenerate fully by stealing the Soul Energy from anyone around him. If he takes away all of someone's Soul Energy, they die.

Quotes

 * (To Nobunaga) "Being able to cry for his companion. I was thinking you couldn't cry, nor did you have a heart. But in that case why... even a little... don't you share that feeling... With all the people you kill !!"
 * (To Chrollo Lucilfer) "May I ask you something? How do you... kill people with no connection with you?"
 * (To Tsezguerra) "I can't do this without Killua."
 * (To Killua) "I swear...I'll take on that bastard myself."
 * (To Neferpitou) "I don't care if this is the end... So I'll use it all. And kill you! Pitou!!"