I have a writing assignment where I have to write a legend or myth or epic about greek gods. My english teacher paired us up to correct each others, but my partner won't do anything. So here is my story (in medias res opening), all mistakes, changes, criticizations are welcomed (I'm grade 8).

“Charge!” cried Athena, as Apollo shot an arrow, killing a dozen zombies. As soon as the zombies hit the ground, more zombies replaced them. Athena slaughtered the advancing zombies with her sword. Her subordinates followed her, destroying countless zombies.
“There’s no end to this!” exclaimed Apollo as he shot a shower of arrows across the mountainous plateau, “There’s too many of them!”
“Someone must be giving commands to these zombies, we need to find that person in order to win this quarrel.” replied Athena as she slashed a zombie who was about to punch her, “Back me up, I’m going the hole where these zombies emerged from.”
“I will.”
Athena charged through the zombies. Apollo shot a silvery arrows in front of Athena, killing an immense number of zombies while creating a pathway for Athena. Athena dashes through the pathway, slashing zombies that took the place of the fallen ones.
The hole was getting closer and closer. Athena could see a dark shadow up ahead, in front of the hole. She could see him now; the evil grin, the bloodthirsty eyes.
“So, Athena, looks like you found me. Now die!”
Ares lunged his sword at Athena; Athena blocked the blow with her shield.
“Your reflexes have gotten faster.” taunted Ares; he drew his second sword and stabbed at Athena’s side “But not fast enough.”
Suddenly, a silver arrow flew towards Ares; he dodged it by a few millimeters. Ares took a few paces back.
“Long time no see, Apollo.”
“Surrender now or we will show no mercy.” Apollo demanded.
“You think the two of you can defeat me and my army of zombies?”
Ignoring Ares, Athena charged at him. Two zombies jumped in front of Ares, blocking Athena’s way. Athena halted her step. While she did so, innumerable zombies formed a wall around Ares.
“There’s no way we can get through all these zombies.” exclaimed Apollo, “We need to retreat for now.”
Without warning, a yellow blur came from the sky and struck Ares in the chest; he died instantly. Zeus then arrived to retrieve his thunderbolt from Ares’ dead body. The zombies, seeing that their leader was defeated, started retreating back into the hole.
“Not so fast!” cried Zeus, as he hurled his thunderbolt at the last zombie to escape. The impact from his thunderbolt caused the hole to collapse.
“What were those things?” Zeus asked.
“I don’t know. I was visiting Athena when they swarmed out of a hole in the ground.”
“It’s not safe here. We should go somewhere else to talk.”
“You have failed me, Ares.”
“I apologize, my lord.”
“Now I must go fight personally.” said a dark shadow as he stood up, “send him to Tartarus.” Two zombies grabbed Ares and dragged him away.
“Please, please spare me! No….!” screamed Ares in despair.
Meanwhile, Apollo, Athena, and Zeus arrived at Zeus’ palace.
“This doesn’t make sense. The zombies emerged from the ground when you and Athena were drinking tea. Afterwards, the two sides had an all out war. Then, you two found out that Ares was their leader.”
“Exactly.” replied Apollo.
“But how could Ares have created all those zombies.” questioned Zeus, “The only person who has the power to create zombies is H-”
Crash! One of the walls collapsed, revealing a massive army of zombies. One of them was blazing with flames.
“Kill them.” said a voice coming from behind the zombies. The zombies dispatched immediately. Zeus threw his thunderbolt. It hit countless zombies. Athena and Apollo got into position as well.
“These wimps cannot defeat me. Come out, whoever you are.” demanded Zeus.
“At least show some respect to your elders, Zeus.” teased Hades as he emerged beside Zeus’s thunderbolt.
“Hades, so it was you.” said Zeus with intimidation, “What do you want?”
“This.” Hades replied as picked up the thunderbolt, “I can create infernos under my control using the power of your thunderbolt. Infernos can only be made when a thunderbolt hit’s a zombie at full force. The one here was created when you threw your thunderbolt at it. I’ll take this thunderbolt back to my lair, then I can create an army of infernos using a machine I built. Using the infernos, I can dominate the whole world!”
Hades disappeared in a flash, taking Zeus’ thunderbolt with him.
“Wait!” shouted Zeus as he was about to chase after Hades. Suddenly, the inferno jumped in front of Zeus, blocking his path. The fires on its body were sizzling, as if it was furious. The zombies assaulted Zeus, Athena, and Apollo.
“You two go on, I’ll fend off these nuisances.” said Zeus. Athena and Apollo departed at once.
After escaping from Zeus’ palace, Apollo and Athena are now having trouble finding Hades.
“Hades is probably using his helmet, so he’s invisible right now.”
“Even though he’s invisible, he will still leave footprints.”
“There are some footprints here, let’s follow it.”
After following the footprints for a while, they arrived at an eerie-looking palace.
“Hades is probably inside.” whispered Apollo..
“Now we need to infiltrate this palace and retrieve father’s thunderbolt.” declared Apollo.
“Let’s go.” replied Athena.
They found an entrance at the side of the palace.
“Be careful, it’s dark inside.” warned Athena. They crept through the darkness.
“There are dead bodies here.” said Apollo, “It also smells bad.”
All of a sudden, a spear came flying at them from the darkness, they dodged it with ease. Apollo shot an arrow to where the spear came from.
“Did you hit something?” asked Athena.
“It’s too dark to tell.” answered Apollo, “Watch out! There are more spears!”
Whoosh! Whoosh! Whoosh! More spears were aimed at Apollo and Athena.
They turned around and ran; countless spears flew at them from the darkness. They had to evade while running. Suddenly, the ground below them collapsed to reveal the never-ending darkness below.
“Ahhhhhh!” screamed Athena and Apollo as they fell. They were buffeted into walls and falling debris as they fell. At long last, they crash landed on to a heap of rocks.
“Where is the place? And what is that?” Athena wondered, looking at a massive structure of pure diamond.
“Look, the thunderbolt!” blurted Apollo as he pointed at Zeus’ thunderbolt the middle of the machine. It’s attached to a heavy looking piece of diamond.
“So you noticed. Like my new machine?” sneered Hades as he stepped out of the shadows, “Kill them.”
Countless zombies jumped out of the shadows and lunged at Athena and Apollo. Athena stabbed a zombie in the chest while Apollo created a skewer of zombies. Like last time, new zombies replaced the defeated ones instantly. Apollo saw an opening in the zombies’ defences. He raised his bow to shoot. But the zombies formed a wall before Apollo even fired.
“These zombies are such nuisances.” said Apollo with annoyance, “Why not we do what we did last time, you charge forward while I watch your back.”
“Great idea.” replied Athena. She drew her sword and charged into the army. Apollo shot continuous showers of arrows in front of her. When she reached Hades, she caught him by surprise. Athena dealt a blow to Hades that sent him flying to his machine. Hades crashed into it, and then he fell down to the ground, unconscious. His zombies merged together to form a barrier around Hades, making it impossible for Athena and Apollo to attack him. Apollo shot an arrow at the barrier, but it simply bounced off.
“What’re we going to do?” wondered Athena.
“We have to wait until Zeus gets here, I’ll bet his thunderbolt can destroy that thing.”
“That’s it! Zeus’ thunderbolt is right there, we can use it to destroy the zombies and Hades altogether. I think his machine is used to create an enormous impact using Zeus’ thunderbolt. The impact will cause the zombies to transform into infernos. However, if Hades is killed, his powers, which are his zombies, will be gone as well.” Athena analysed, “Do you see those dials? I think those are the controls.”
“You wait here; I’ll go control the machine. Be aware of any signs of danger.”
Apollo ran to the machine and jumped on to it. He deftly scaled the structure. Before long, he reached the controls. There were a power gauge and a red button. Apollo switched the power gauge to full power and pressed the red button. The instant he pressed it, the whole machine came to life. This machine spoke in a mechanical voice “Preparing to fire at full power. Warning: The amount of power used will cause system to explode.
The machine shook wildly. Apollo jumped down from the machine.
“We need to get out of here, it’s going to explode!” shouted Apollo.
“I found way out while you were configuring the machine. This way!” said Athena, as she led Apollo to a dwindling staircase. They ran as fast as their legs could carry them. They could hear the machine down below.
“Firing in 10, 9, 8...
The exit was in sight.
4, 3...
Only a few meters to go.
Athena and Apollo were out just in time. Behind them, the deafening explosion left a massive fissure in the ground. Hades was defeated. When the smoke cleared, no traces of the zombies could be found. Zeus’ thunderbolt was found erected in the center of all the damage. Zeus arrived; he reported that the zombies that he was fighting suddenly all disappeared when he heard an explosion in the distance. He got his thunderbolt back. There will be no more zombie attacks - for now.