Being a hero means being selfless. Despite the fear one may feel, despite the impossible odds looming before them, a hero steps up and does the right thing even if it could cost them everything. That's exactly what James Rhodes, aka War Machine, the partner/successor to Iron Man did when he fought the Omega-level mutant Exodus in 1995's Avengers and X-Men crossover "Bloodties." With the fate of all of humanity resting on his shoulders, War Machine engaged the staggeringly powerful mutant in a battle that could have cost him his life.
The future of the world hanged by a thread. Following Professor X's mindwipe of Magneto a power vacuum had opened up in his absence. Fabian Cortez, the original creator of the Acolytes and would-be usurper of Magneto's station, had been cast out by Exodus. Cortez, desperate to maintain power, manipulated the mutates of the island nation of Genosha to help him kidnap Luna, the daughter of Quicksilver and Crystal. With a young girl as his hostage, Cortez incited civil war between mutates and humans, the first act of a genetic war.
The X-Men traveled to Genosha to rescue Luna while the Avengers traveled to Genosha in an effort to halt the civil strife before it became worse. The forces at play were dizzying: Fabian Cortez sought to instate mutants as rulers of Earth; Exodus sought to avenge the betrayal of Magneto by hunting Cortez while also furthering his mission of mutant supremacy; Quicksilver and Crystal, with the help of Scarlet Witch, sought to rescue Luna; and the warring factions of humans and mutates sought only to kill each other.
As both the West and East Coast Avengers united for the mission, it was War Machine that initiated the first battle against Exodus after witnessing him murder an entire crowd of humans. It was a battle that War Machine could never hope to win. Even equipped with the finest Stark tech and the most cutting-edge combat suit, the unfortunate truth was that War Machine was still just an average human fighting one of the most supremely powerful psionics on Earth. War Machine was able to land a few blows against Exodus which is far more than most of his allies, X-Men and Avenger's alike, could say. But not his armored fists, his spray of bullets and rockets, or ramming the entire suit itself into Exodus was enough to slow him down. A single psionic attack directly into War Machine's mind was enough to completely incapacitate him.
Sersi, an Eternal and member of the Avengers, engaged Exodus after War Machine was taken out of the fight. In a stand-off that threatened to destroy the entire island, Sersi was able to match Exodus' power but had to be convinced to fall back the confrontation was causing widespread destruction. As the battle between Exodus and the two teams of heroes grew to a frantic pitch with a giant energy field crushing the entire island of Genosha around them, it was a daring attack by Black Knight that put an end to the mutant's threat.
Despite not scoring any critical hits against Exodus, War Machine still earned the right to call himself an Avenger when he chose to battle him. The time he spent keeping Exodus busy was time Exodus could have spent killing more innocent people or even a member of the Avengers. To stare into the face of one of the most powerful beings on the planet and choose to confront him was a feat of pure bravery...and the true mark of a hero.