DISCLAIMER: I do not own the Avengers or the Justice League.
The Justice League settled themselves in a field, preparing to face the Avengers. Captain America and Iron Man stood at the front of the Avengers, while Superman and Batman stood at the front of the Justice League.
Thor spun his hammer around in a windmill motion, before launching himself into the crowd of Justice Leaguers. Green Lantern created a wall of machine guns, which fired shots at Thor, which hurt him, but didn't seem to penetrate his skin. Thor slammed into the wall of machine guns, shattering it. Wonder Woman then flew into him, collecting him.
Flash dashed to the Avengers, slamming the flat of his foot into Hawkeye's midsection, knocking the archer out in an instant. Black Widow attacked the Flash, but he easily avoided her. Iron Man took to the sky, shooting missiles at the Justice League. Superman used his Heat Vision to destroy the rockets before they reached the League, and Captain Marvel retaliated with a bolt of lightning, which he flung at Iron Man.
Green Arrow fired several arrows at the Avengers, before Captain America stood over him. Iron Man and Spiderman charged into the Justice League's ranks, where they were met with rock hard resistance from Captain Marvel. The two teams then charged each other as one, and the fight truly began.
Some of the combatants were defeated very quickly. Iron Man was punched into the air by Aquaman, and then fired a series of missiles at Wonder Woman, staggering her slightly, and leaving her completely open to the series of hammer strokes she received from Thor, which knocked her out. Iron Man was then pulled from the air by Captain Marvel, who slammed him down onto the ground repeatedly, knocking him unconscious.
Captain America struck Green Arrow back several paces, where Green Arrow was punched unconscious by Spiderman. Spiderman was then knocked unconscious by a wall dropped on him by Green Lantern. Flash was then hit by Thor, and knocked unconscious in a single blow. Thor then engaged Green Lantern. Captain Marvel punched Storm in the face, knocking her out in one hit. Black Cat was then knocked out by a surprise attack from Catwoman, who was herself knocked out a second later by a passing blow from Captain America's shield.
Aquaman punched Black Widow flying back, instantly rendering her unconscious, as Thor slammed his fist into Green Lantern, knocking him out and sending several of his teeth flying in multiple directions. Thor and Captain Marvel then slammed into each other, while Aquaman prepared to engage Captain America, the only other Avenger left standing.
Thor defeated Captain Marvel, but it took great effort as the two were in close quarters, where Thor couldn't use his lightning to revert Marvel to Billy Batson. As Captain Marvel fell, unconscious and badly bruised, Superman's fist collided sharply with Thor's face, stunning the Asgardian. Meanwhile, Aquaman was punched unconscious before he could even reach Captain America, his attacker stepping in front of Captain America. It was the Hulk.
Superman moved over to Hulk, ready for the last battle that would decide the outcome.
Batman walked next to him. "That's the World-Breaker Hulk, and he seems angry. Be careful, Superman."
Superman stood in front of the Hulk, while Batman prepared to face Captain America.
After a second to compose themselves, the four remaining combatants charged. The final battle was at hand.
