After his village was slaughtered by a demon with pink hair, Goku started his journey to reach Mount Sagiri, where Urokodaki Sakonji lived, to train under his wing.
"I wonder if he'll accept to train me..." said Goku to himself. Finally, after a long journey, he reached the top of Mount Sagiri. Tired, Goku opened the door of Urokodaki's house. Once he did so, Goku saw a old man with a red Tengu mask.
"Are you Urokodaki Sakonji?" Asked the boy.
"Yes," answered Urokodaki, turning to face him, "what do you want?"
"Train me," said Goku, without wasting time, "I want to become a demon slayer."
"So you don't knock, don't greet, and just waltz in here, wanting me to train you? You're bold, boy," answered Urokodaki, "but I'll train you anyway. But only because I feel you might be strong under a good mentor."
"But I'll train you only if you manage to climb Mount Sagiri again."
"Fine," said Goku, "I'm in."
Then, the boy got guided at the beginning on Mount Sagiri.
"If you manage to return on top of the Mount before the sun rises, I'll train you," said Urokodaki. Then, he disappeared into the shadows.
"I have to return at the top..." said Goku. But then, when he took a step closer, a trap activated. A massive trunk spawned from nothing, hitting Goku right in the face. The boy rolled down and fell on the floor, coughing.
"Okay... This might be harder than I initially thought."
After a long time, and after he had understood how the traps worked, Goku managed to climb the top and return inside Urokodaki's house.
"I'm... here..." he said, coughing and panting. Then, Goku fainted, breathing heavily.
"And so, he really managed to return..." whispered Urokodaki, "I recognize your value and accept to train you, Goku."
Three years later. Three years had passed since Goku started training under the wing of Urokodaki Sakonji. The boy, now nineteen years old, has become a skillful swordsman. But still, he couldn't manage to padronize none of the available Breathing Styles. One day, during his training in the forest, Goku swinged his sword in the air.
(Three years has passed, but still, I can't use any of the Breathing Styles...) he thought. (I tried Mist, Wind, Water and Thunder... But nothing.)
After a while, Urokodaki walked towards Goku.
"Goku... You are a great swordsman, but I can't allow you to the Final Exam until you learn a Breathing Style," he said.
"I know," said Goku, "I wanna try to use Flame Breathing. That's the only Style I've never tried to use."
"Fine," said Urokodaki, "Try it, then."
Another week passed. During this span of time, Goku learned to use only one form of the Flame Breathing. Flame Breathing: Third Form -- Blazing Universe. That was the name of the form.
"Finally, I managed to learn a Breathing Style, even if it's only one form..." said Goku.
Urokodaki, next to him, spoke up.
"Goku, you finally learned a form of a Breathing Style. You're ready for the Final Exam," he said.
"Fine," said Goku, "I'm ready."
"Oh, anyway... What's the Final Exam about?" Asked the boy.
"You're gonna stay in a mountain full of demons for one week straight. If you succeed, you become a demon slayer. If you fail, you die," explained Urokodaki.
"Fine. It doesn't seem so hard," said Goku, with a bit of boldness in his voice.
The next day, Goku was brought to the mountain.
"Here we are. Are you ready?" Asked Urokodaki.
"Of course I am," answered Goku.
"Listen, before I leave, I have a question for you," said Urokodaki, "hat's your surname?"
"I have no surname," replied the boy, "my name is just Goku."
"I see..." sighed Urokodaki, patting Goku on a shoulder and leaving, "good luck, Goku with No Surname."
Goku walked towards the place where the other slayers where. Then, two girls with white hair showed up.
"Welcome, apprentices slayers. Today, your final exam begins. If you survive, you become a demon slayer. If you lose, you die. Are you ready?"
Goku nodded silently. And then, the boy started to walk inside the forest, where the demons lurked. Goku's Final Exam began.
As Goku entered inside the forest, he already started to see the demons.
"I don't fear you, demons..." he said, holding his sword.
The first day was easy. Goku survived without breaking a sweat.
The second and the third day, things started to get a bit harder.
On the fourth day, Goku heard another boy's scream.
"Ugh... Guess I have to save him..." he sighed. As Goku arrived, Goku quickly beheaded the demon from behind, saving the boy.
"T-thanks... What's your name?" whispered the boy.
"Goku," said Goku, "what's yours?"
"Murata," replied the boy.
"Nice to meet you, Murata," said Goku, walking away with his sword on his shoulder, "I hope you survive for these remaining days.."
"T-thanks..." whispered Murata.
On the last day, Goku faced a demon stronger than normal, but he eventually survived.
Goku eventually returned to the place where his Final Exam hag began.
"Welcome back, slayers. You survived, that means you're officially demon slayers now," said the same two girls who spoke up one week ago, "now, you can choose your Kasugai crow, and then get your personal katana."
And so, Goku stepped forward and chose the third crow of the row. "It's female," said one of the two girls.
"Female? Then I'll call her Rin. Just like my mother..." whispered Goku, taking the crow with him.
The crow looked at him and noised, "Caw!"
Later, Goku reached Urokodaki's house.
"I'm back, Urokodaki-san," he said
"I'm glad, Goku," said Urokodaki, "I guess you're here because you know I have your katana, right?"
"That's exact," said Goku. And so, Goku received his katana. The katana had a white handle, with blue flames on the blade and the rest of it white. His haori was light blue, with orange flames at the edge of it.
"I've got the crow, the haori, the brown suit and the katana... Is anything missing?" questioned Goku.
"No. You're ready to go, Goku," answered Urokodaki.
"Thanks for everything, Urokodaki-san," said Goku, hugging his mentor, "see ya." said Goku.
(Might your path be safe and full of joys, Goku with no surname...) thought Urokodaki.
And finally, Goku's journey as a demon slayer officially begun.
Chapter 2 - End.