Early Years
James Proudstar was born on the Apache reservation in Camp Verde, Arizona. As a young boy, James idolized his older brother, John Proudstar, and when John returned from a stint in the Marines, James was overjoyed to see him again. Unfortunately, their mother revealed to the family that she had cancer, prompting a visit to an amusement park, where James had his fortune told to him, by none other than Destiny, though James thought she was a fraud. Then, James secretly accompanied John, when he infiltrated Arroyo labs, the clinic that was running tests on their reservation's people and treating them for cancer. James was discovered by Dr. Edwin Martynec, who revealed himself to be a mutated werewolf. The brothers learned that Dr. Martynec was faking the cancer diagnoses, so he could irradiate his patients and observe the results.

John was soon recruited to the X-Men and was killed on one of the team's first missions. James blamed the X-Men for his brother's death and promised to murder its founder, Professor Charles Xavier. James soon manifested his own mutation, similar to his brothers'.

Hellions
James soon joined the Hellions, at the Massachusetts Academy, under the leadership of The White Queen, where he was tutored, by the White Queen, and trained in the use of his powers. James first encountered the New Mutants, after the White Queen invited Doug Ramsey to her school and she captured Kitty Pryde and Doug. Emma Frost was unaware that Kitty and Magik shared a rapport and the New Mutants came to their rescue. James later donned his brother's costume and kidnapped the X-Man Banshee, to draw the team to Cheyenne Mountain, where his brother John had been killed. Everything was going just as planned for him, but at the last second, James couldn't bring himself to kill Professor X. Professor X, eventually, convinced Thunderbird that his brother died a hero's death and James released them, stating Professor Xavier was an honorable man. Professor X offered James membership into the New Mutants, but he declined. Instead, James rejoined the Hellions and eventually became the leader.

Rivalry
The Hellions and New Mutants began a rivalry, which both headmasters slightly encouraged, but after the New Mutants were sent to the Massachusetts Academy, James gained a respect for his rivals and a crush on their leader, Dani Moonstar. The New Mutants were returned to the Xavier's School for Gifted Youngsters and later Magneto dressed them elegantly and they all attended a Hellfire Club event, where James befriended the honorable Dani. The pair began to search for Wolfsbane and Catseye, who had run-off in their lycan forms. The event turned sour for the rest of the New Mutants after finding Cypher, drunk, in a bed with Roulette, until Cannonball suggested another duel between the two teams. The duel was for both teams to hunt down the person responsible for selling a member of the Hellfire Club a forged statue of Selene and the losers were to apologize, publicly, for any insults and take the rap for any trouble with their teachers before sunrise. After having Illyana Rasputin spy on the Hellions, through a scrying glass on Limbo, the New Mutants learned that Viper and the Silver Samurai were behind the forgery and decided to intercept the villains, before the Hellions. Unknown to the New Mutants, Thunderbird assumed that they would spy on the Hellions and led them to the henchmen of the villains, while the Hellions captured Viper and Silver Samurai, winning the competition. Upon returning to the Hellfire Club, while James was positioned to kiss Dani, Tessa arrived with a letter from Xi'an Coy Manh, for Dani. After hearing of an animal creature that was being mistreated after capture, Emma allowed the Hellions to participate in a contest with the New Mutants to abduct Bird Brain, where Thunderbird was influenced, by Empath, to admit his crush on Dani and the New Mutants emerged victorious.

X-Force
James soon felt like he did not fit in with the Hellions and quit, and returned to the Apache reservation in Camp Verde, Arizona. Cable soon met with James and offered him membership into his New Mutants, but he declined, as he enjoyed staying at the reservation. When James returned, he found the entire tribe murdered, and a Hellfire Club agent's mask left behind. James then decided to join the New Mutants, from his newly formed vendetta against the Hellfire Club and Emma, in particular.

Under Cable's leadership, the New Mutants no longer associated with the X-Men and James took on the codename Warpath. Alongside X-Force, he fought the M.L.F., the Brotherhood of Evil Mutants led by Toad, and many other villains that crossed their paths. When James later met Emma again, she claimed she had no ties to the killings of his tribe.

When Cable moved X-Force back to the X-Mansion, he tried to get Warpath to train with a bo staff, which he did for a short time, but never used in action. By this time, Warpath was experiencing an increase in sensory awareness and strength that allowed him to perform feats he never imagined before, such as run at 100 MPH and climb walls by digging his fingers into the concrete. One night, he received a message regarding the massacre's perpetrators and ran to New York, where Risque introduced herself to him from the shadows, planted a kiss on his lips and left.

Then, when Selene made her move against the X-Ternals, killing those who remained, Warpath sensed her presence in Gideon's apartment and climbed the building to find it. He was able to track Selene, but fell victim to her spells and was knocked out. Fortunately, Risque arrived and pulled James out before Selene could drain his life. Risque took James to Florida to recuperate and they fell for each other. Finally, Jimmy wanted to get back to his friends, and the duo arrived just in time to defend X-Man from Mister Sinister. Warpath intended to remain at the Mansion, but after being confronted by the Blob and Mimic in NYC, Risque finally fulfilled her "mission" by slipping a sleeping pill into Jimmy's drink and brought him to Sledge in Detroit.

Sledge had no malicious intent, but rather offered James the location of his tribesman Michael Whitecloud, who had somehow survived the massacre on the reservation. In return, he asked Warpath to enter a dimensional gateway and retrieve the person who was trapped there. That person ended up being the Vanisher, and James rocketed him out of the dimension with his vacuum suit's jetpack. As a result of this experience (in which he almost ended up trapped forever telling stories to the dimension's natives), James began to question his constant searching for vengeance and his focus on the past. James got Whitecloud's location from Sledge and went to see him with Siryn. Whitecloud told Warpath the more about the massacre and how he escaped and how to access the files he stole from the Arroyo Institute, which was the reason for the destruction of Camp Verde. However, Whitecloud's head exploded before he could reveal the names of those who sponsored the massacre. James retrieved the documents, but was ambushed and captured to Martin Edwards (Edwin Martynec), who was waiting for him. Martynec revealed that he had been working for Stryfe to create mutated soldiers and experimented on the people at Camp Verde, but the escape of one of his doctors and one of his creations necessitated the massacre as a cover up. Siryn and Warpath broke free but Martynec injected James with a drug and killed him.

In a hell dimension, Warpath was confronted by Stryfe, who wanted to force him into despair, which would allow Stryfe to be resurrected by Blackheart. Fortunately, Jimmy was able to connect with Siryn, who was doing CPR on him. Also, Valkyrie (Brunnhilde), brought the rest of X-Force to the hell dimension to fight for Jimmy's soul, and they won, returning Jimmy to life.

Under Pete Wisdom's tutelage, James learned how to use his enhanced abilities to do things he never thought of, like fly. Exactly how he manipulated his power to do this is still unknown. James remained with X-Force through Wisdom's tenure and through one faking of the team's death. However, when X-Force came upon a top-secret plot to use alien technology to recreate a planet-moving engine, they apparently could not stop the bio-engineered defenders of the facility. James and his teammates (except Domino) were presumed dead following the explosion they set off, leveling the alien tech base. However, they soon appeared at a press conference for the new team calling itself X-Force, and got into a fight with the other mutants over naming rights.

Shortly thereafter, James was recruited into the Mumbai, India office of the X-Corporation. When Professor X came to visit, James saved his life from assassination by the deranged Lilandra. He worked with former teammate Feral, her sister Thornn, and Sunfire. Before receiving his X-Corporation uniform, he was wearing his brother's old costume, which the Indian public adored.

X-Men
As a result of the Scarlet Witch's actions during the "House of M" incident, nearly all of the mutants in the entire world were stripped of their powers, although James retained his powers. As a result of the loss of mutants, Cyclops shut down all of the X-Corporation offices and most of the X-Corporation employees were sent to the Xavier Institute. Warpath was one of the many, including his former Hellion teammate, Empath. James did not enjoy his stay as it reminded him of a reservation he grew up in. While living on the Xavier grounds, James rekindled his friendship with former teammate Caliban who was also staying on the grounds. He also was given Vibranium Knives as a gift from Storm and the Black Panther.

Shortly afterwards, he joined the ranks of the X-Men for the first time, at Professor X's request. Along with Professor X, Marvel Girl, Nightcrawler, Havok, Darwin, and Polaris, he journeyed into space to track down Vulcan. He showed his superb fighting prowess while fighting cyborg drones as the X-Men attempted to commandeer a Shi'ar ship. During the final fight with Vulcan, Warpath fought bravely and in the end was on the spaceship with half of the team when Lilandra sent it back to Earth.

Back on Earth, Warpath was training with Hepzibah when they came across Sentinels attacking a "trespasser", who turned out to be Caliban. Nightcrawler teleported Caliban away to the infirmary and Warpath threatened the Sentinel until Storm showed up putting the Sentinel pilot in an awkward situation.

Caliban soon told them of Leech's kidnapping, and Masque's return. The X-Men journeyed to the Morlock Tunnels, and Warpath fought an alligator along the way. Caliban explained that the alligators were their protectors and a girl could talk to them, but Warpath told him that she was gone and they were not listening anymore. While wrestling it, he was thrown through a wall, and on the other side found cryptic writings of Qwerty. They soon found where Leech was taken, and saved him while defeating renegade Morlocks in the process.

The New X-Force
Warpath, along with Hepzibah, Caliban, Wolfsbane, X-23, and leader Wolverine formed a new X-Force designed to personally do the extreme tasks the X-Men would not normally be associated with. During Messiah Complex, Caliban sacrificed his life to save James' by jumping in the path of a range of bullets from a Reaver.

James buried Caliban at his past Apache reservation, alongside his brother and continued to fight alongside X-Force, as well as date Hepzibah. While taking some time off from X-Force, he visited his brothers' grave, and was attacked by a disturbed Demon Bear. With the help of Ghost Rider, he learned the secrets of Eli Bard; how he had ressurrected his brother, Caliban, and his tribe for a sacrifice to Selene.

Necrosha And Afterwards
After the Messiah War, X-Force was thrust into the middle of Necrosha, where reanimated past villains and the likes were controlled by Selene and the T-O virus. He met Risque, who was a part of Selene's resurrected army, and she managed to fight the T-O virus long enough to tell him to get away. When he confronted his brother, he gave him a mercy killing. Later, with the help of an ancient ritual, he defeated Selene by stabbing her in the heart with her own dagger, which also freed the souls from her reanimated army.

He later left the X-Force team, and was seen staying on Utopia afterwards.