Bruce is a genius as an expert in gamma radiation. He is overly sarcastic by guessing Hawkeye's joke. After having exposed to the gamma bomb he gained another personality that is monstrous, called the Hulk, that he can change into after his heart rate goes at a certain point by getting too excited or angry. He tries to maintain his heart rate by calming himself down,but it seems that he's able to bring out Hulk by will alone.
The Bruce persona is that of a kind doctor who likes meeting new people, such as Tony Stark and Steve Rogers, although he is not without a sarcastic side. He is a brilliant scientist whom Tony Stark likes and he makes great work which makes him a great scientist as well. Given that Bruce also sometimes can feel a little upset or angry and depending on what he's feeling. When he transforms into the Hulk then that means he's angry and he's not happy at all. But Bruce is a very nice guy and always helps out, even when it's very difficult for him to fit in with other people. He is known to also be very smart and intelligent and he knows what he's doing when he's performing experiments in his lab or workplace.
As the Hulk, he is very aggressive especially when he changed into the Hulk when he was angry, after changing into the Hulk, he causes destruction to his surroundings and beats anything in his path, however, he has a soft spot for animals. After some time, Hulk respected people and had the thought of helping them instead of hurting them, such as when the Hulk rescued Hawkeye's men from a helicopter crash. He can get along with people very well, but can be easily irritated by others if they think that Hulk is only a monster.
Powers and Abilities
Transformation: Due to the Gamma Radiation that has mutated his body, Bruce is able to transform between his normal, unpowered human form and the form of one of the most powerful superhumans. Bruce has trouble with this ability as it only activates by pure aggression and requires force of will to summon it. In addition, this transformation has led to a dual consciousness, with one being Bruce and the Hulk. As of now, the Hulk is in charge of their shared body. He has only transformed back into Banner a handful of times.
Superhuman Strength: As the Hulk, Bruce has virtually unlimited superhuman strength at his disposal. He is strong enough to match his teammate Thor in combat, as well as break through the incredibly powerful gravitational influences of the villain Graviton. He is easily able to heft objects like tanks with one hand and use them akin to a baseball bat. Frankly he is capable of picking up any object he wants to. Bruce's strength increases when he is angry, and this is something that has led to the downfall of many villains.
Superhuman Durability: As the Hulk, Banner possesses near-invulnerability toward all types of harm. He has been struck with bullets, laser cannons, powerful magical and technological energy blasts, and falls from great heights with no injury. His durability is similar to that of Thor, Ronan the Accuser, and the Thing.
Environmental Adaptation: As the Hulk, Bruce can adapt to any environment, even airless space. Bruce can adapt to a wide diversity of hostile habitats. Bruce can harmonize his biological structure with the depths of the ocean. He can even speak in these inhospitable habitats. Bruce can eat, drink, breathe and function normally in any environment. He does not need to eat, drink, or breath, and his ability to adapt to his environment is an inherent property, which is also enhanced and amplified by his rage, excitement, stress, and necessity.
Weaponizing: As the Hulk, Bruce had to make something useful out from any object and used them as melee and ranged weapons like tanks, missile launchers, signboards, cars on foes.
Accelerated Healing Factor: Hulk can heal even serious wounds within seconds. These attributes make him extremely difficult to kill, even if he is in his human form.
Superhuman Endurance: Bruce's body generates no fatigue toxins during physical activity, granting him nigh limitless endurance in all physical activities. His stamina and vitality are inexhaustible and limitless.
Superhuman Stamina: Bruce's stamina and vitality are inexhaustible and limitless.
Superhuman Speed: Bruce is capable of running faster than a human; Hulk could even surpass an aircraft while on land, he can swim at 100 knots, and keep up with Emil Blonsky. His reflexes have even been described as "lightning-fast reflexes", fast.
Advanced Hand-To-Hand Combatant/Martial Artist: Although he has not be formal training in hand-to-hand combat and martial arts; his fighting skills combined with his superhuman physical attributes, makes Hulk a formidable opponent alone in single combat. In his human form, Bruce received training in hand-to-hand combat and martial arts; in Brazil from a hand-to-hand combatant and martial artist expert.
Genius-Level Intellect: Bruce possesses a genius-level intellect, famous for being one of the foremost geniuses of his generation.
Master Scientist: Bruce is one of the world's renowned scientist in fields such as Biochemistry, Nuclear Physics and, especially, Gamma Radiation.
Expert Tactician: Bruce is an extremely skilled tactician.
Multilingualism: Bruce is capable of fluently speaking English, Portuguese, Spanish and Hindi.
The Incredible Hulk
In an incident he was exposed too Gamma Radation, when he was trying to recreate the Super Soldier serum that was used on Captain America but instead transformed him into the Hulk.
Later, he was living in India as a Doctor, living a quiet life he was tricked into meeting Natasha Romanoff and was inducted into the Avenger Initiative to assist with locating the Tesseract.
After meeting the rest of the members; Thor, Tony Stark, Steve Rogers. He befriended them, and begin working with them to locate the Tesseract along with Stark. He and Tony also spoke with Captain America, for Fury's reasons for the Tesseract.
He also was manipulated by Loki's scepter but was able to snap back as the computer began locating the Tesseract however at that time Hawkeye, who was brainwashed by Loki begin an attack on the Helicarriers which made Banner transform into Hulk and when on a rampage.
He eventually turned back into Banner, as he arrived to the Battle of New York and rejoined The Avengers to assist them as well as apologize to Romanoff for earlier attacking her. He finally controlled his anger, claiming he is always anger and transformed into the Hulk and began attacking the Chitauri and the Leviathan.
Hulk also entered Stark Tower and simply beat Loki with no effort saying "Puny God", after defeating him and rejoined the battle.
Later, World Security Council ordered Fury to send a nuclear missle at New York to neutralize the threat but would kill a whole lot of people, he dismissed the order and the Council had someone hijack it but Iron Man flew it up at the Chitauri wormhole destroying the army and saved Iron Man as he fell.
Later, after the battle they all eat at the Shwarma palace which Stark suggested and were interrupted by War Machine who arrived late to assist in the battle. Later, as Loki was send back with Thor to answer for his crimes and with the Tesseract he and Stark left together as the Avengers went separate ways.
Sometime later, Tony Stark went to talk with his friend Dr. Banner to talk about his tantrums but he fell asleep as soon as the session started but Tony just kept telling him more of his stories, making him fall back asleep.
A couple of years since the Battle of New York, the Avengers discovered the location of the scepter that was in a HYDRA base in Sokovia. They attacked the base, and recovered the scepter. When they returned to the tower, Stark convinced him to assist him with creating Ultron a peacekeeping intelligence robot as everyone leaves J.A.R.V.I.S. awakens Ultron who instead goes Rogue and kills J.A.R.V.I.S..
After the victory, Stark organized a party and during it he flitters with Romanoff making him realize the two has feelings for each other and while the Avengers attempted to lift Thor's hammer they were all unsuccessful including Banner than Thor teased them. They were than attacked by Ultron and the Iron Legion which Ultron forced them to attack them. After a brief battle, they managed to destroy Ultron but was able defeat it but claimed it would return.
They later learned, Ultron had made himself a new body Wolfgang von Strucker and was planning to steal Vibranium from Ulysses Klaue. During the battle from getting Ultron to acquire the Vibranium Banner stayed in the Quinjet but got manipulated by Scarlet Witch's abilities turning him into the Hulk and made him attack the city in South Africa but was eventually defeated by Iron Man in his Hulk Buster armor.
With the public ridiculing them for his rampage, Banner along with the Avengers took refugee at Clint Barton's home. There, Banner and Widow planned to elope after they defeat Ultron.
Nick Fury also arrived at the homestead, to speak with them.
A year after the Battle of Sokovia and Banner going off the grid, when an incident occurred in Lagos with Scarlet Witch accidently killing many people in Lagos when stopping a bomb set of by Crossbones to kill Captain America. Thadduess Ross now Secretary of State visited The Avengers at their facility to present the Sokovia Accords, Banner was mentioned by Ross along with Thor if Cap knew their location of one of the reasons of the Accords.
Ross than showed footage of the constant collateral damage of The Avengers missions; Battle of New York, Battle at Treskilion, Battle of Sokovia and Mission in Lagos. One of them during the Battle of New York, Hulk was hopping from building roof to roof however causing debris fall and hit citizens.
In Avengers Assemble, Hulk has a collection of glass animals that he is very fond of, referred to as "The Zoo" by Iron Man and Captain America. Made for him by Glorian, an inter-dimensional craftsman, each one represents a different adventure he has had over the years. Anyone who breaks one of his glass figurines earns his instant wrath, as Hawkeye discovered to his dismay in the episode "Mojo World". Most of the Avengers have learned to steer clear of "The Zoo".
Ultimate Spider-Man features an alternate, grey version of the Hulk known as "Mr. Fixit".
In the animated series, Hulk rarely becomes Bruce again.