Clash of the Rexes: Rexy Vs. Bull T. rex Vs. Indominus rex Vs. Vastatosaurus rex

Here we go...

Rexy

Length: 40 ft

Strengths: size, speed, strength, bone crushing jaws, binocular vision, experience 

Weaknesses: old age, not very smart

Bull T. rex

Length: same as Rexy

Strengths: same as Rexy except experience 

Weakness: not very smart

Indominus rex

Length: 50 ft

Strengths: size, strength, endurance, tough skin, camouflage, intelligence, claws, jaws

Weakness: weakest bite (but it's still strong)

Vastatosaurus rex

Length: 60 ft

Strengths: same as Rexy and the Bull T. rex, but much stronger (same speed as them though)

Weakness: same as Bull T. rex

Arena: Jurassic Park visitor center, Isla Nublar

Fight!

The Stegosaurus foolishly strayed from his herd, wandering to a clearing in the forest. He stood in front of the JP visitor center, eating a plant. Hiding in the bushes was the camouflaged Indominus rex. She charged, revealing herself. The Stego turned too late. The hybrid's jaws clamped down on his head. Her head jerked back, decapitating the herbivore. She ate large chunks of flesh from the Stego's side, ripping bones and muscle out. The herbivore's entrails even spilled out. The I. rex only ate part of her kill, then camouflaged and went to sleep. 

Miles away, Rexy, queen of the island, was on the hunt. She found a Stego herd and began scanning for a target. The Tyrannosaur found one who had strayed from the herd. Creeping through the bushes, Rexy got close to her prey, then bit his tail. He struggled, but the queen refused to let go. Suddenly, she felt a sharp pain smash into her leg. She turned around, seeing the herd. Standing in front of them was the Stego who had hit her, his tail dripping with her blood. The angered Rexy limped away, but picked up the scent of another Stego. She found the I. rex's unfinished meal. The smell of rotting flesh blocked Rexy from sniffing the I. rex out. She began to feast, waking up the Indominus. Uncloaking, she stood up, roaring at the T. rex. Rexy looked up, growling back. 

Meanwhile, a mated pair of T. rexes walked through the woods, their one son following. The male, a large bull, picked up the smell of a dead Stegosaur, ordering his mate to guard the baby. This was going to be a game changer for them; the trio hadn't eaten in weeks. The male continued on, finding Rexy and the hybrid growling at each other. He revealed his presence with a loud roar at the other two rexes. The three growled at each other, then the bull began to drag the dead Stego back to his family, who watched from a safe distance. Rexy attacked him, biting his neck. He shook her off and the two growled, but then a massive V. rex appeared. Suddenly, the I. rex rammed the V. rex, smashing him into a tree, loosening it. Rexy attacked the hybrid, who shoved her down. The I. rex approached, but Rexy roared defiantly and kicked her away. 

Meanwhile, the other T. rex took advantage of the V. rex's fall, biting his leg. The larger rex roared, clamping down on his back. He screeched in pain as the larger predator slammed him into a rock. The V. rex then rammed Rexy, knocking her over. The hybrid approached, but the male T. rex headbutted her, smashing her ribs. Rexy realised he had saved her. The two T. rexes growled lowly, forming an alliance. 

The V. rex roared, and the I. rex answered the call. The two T. rexes snarled at both of them. They flanked the V. rex, knocking him down. Rexy took advantage of his fall, smashing his skull with her giant foot.

She faced the hybrid and the two jawlocked. The I. rex threw her into the visitor center, then stomped in after her. But the bull saved her again, biting the I. rex's neck. Rexy got up, roaring. The hybrid cloaked, but Rexy slammed her tail down on her head, causing her to reveal herself. She then grabbed her, throwing her through a wall. The three rexes were now outside again, with the I. rex ramming the bull and biting his neck. Rexy intervened and bit the hybrid, making her lose her grip. She shrugged her off, slamming Rexy to the floor.  But the male T. rex came again, biting the I. rex. Rexy was exhausted and watched. She would die, but at least her teammate would be able to feed his family. Then, the worst happened. The hybrid broke free, slashing the bull and shoving him into a rock. He collapsed from blood loss, exhaustion, and shock.

Rexy roared, as if she was shouting "NO!"  She stood up, facing her foe. The I. rex charged, but Rexy dodged. She felt a horrible pain. Her injuries, along with her old age, were slowing her down. Rexy limped over to the loosened tree. As she hoped, the hybrid followed. She waited for the right moment, then SLAM!  The tree fell on the I. rex, smashing her already damaged ribs.  Several branches pierced her hide, blood spilling everywhere. Rexy bit her lower jaw and pulled, ripping it clean off. She had beaten her opponent, but she was concerned about the male rex. The warrior limped over to him. He was injured, but alive. Standing up, he allowed Rexy to join his pack as the matriarch. They joined his mate and child, feasting on the dead herbivore. The Tyrannosaurus rexes left the area, but Rexy stayed for a little while longer. The visitor center was the sight of two of the biggest battles of her life. As she left, she thought about the building. The queen had a special place in her heart for it. It would be part of her kingdom. 

Years later, the son of the Bull T. rex arrived at the site. This was his first hunt. Spotting a Stegosaurus herd, he crept through the bushes using the techniques Rexy taught him...

Winners: Rexy and the Bull T. rex

Please give me feedback via the comments. If this does well, I'll do T. rex Vs. Spinosaurus Vs. Giganotosaurus Vs. Carcharodontosaurus!