What if Tanjiro was a Pure Saiyan? (DB X KNY)

Boy Turned Demon

*Chapter is set sometime during the four months after Tanjiro defeated Hakuji. Heads up! A pretty cliché backstory is incoming!*

- 3rd Person POV -
It was around evening and Tanjiro flew into his next mission where he was informed of a demon sighting. He thought to himself, "I'm pretty sure this is where the crow told me to go. I mean he did say a house in the Southwest area." He began to reach into his haori and grabbed a rice ball. He ate it while looking down below for his location. He said, "Is this the house that the crow told me about? I'm gonna check it out." He dropped to the ground and began to converge on foot. He felt a presence and thought, "Well I think this is it. This presence sort of feels demonic and kind of powerful. I better be careful." He finally reached the house he was informed of. Beside the house, there was a shed that housed the demonic presence. Tanjiro went inside the house to see if anyone was either alive or home. He knocked but there was no answer. He knocked again but again there was no answer. He entered the house and found the stuff inside it was tampered with recently. Most notably a jar that had Yen. He picked up the jar and smelled it. To his surprise, it smelled like a human boy. He thought, "Does whoever know that there is a demon inside their shed? I better kill it before they were to find out and get killed." Tanjiro then exited the house and slowly crept to the shed. He thought, "The demon seems powerful with its presence. I better not hold back or it'll destroy anything if I'm not careful." He slammed the door open and was greeted with talons almost scratching his face. He barely dodged it and thought, "What the?! How did it know?" The demon was about to charge Tanjiro but was held back by very strong chains that held it back. Tanjiro was confused and asked, "Hey! What's going on? Can you speak?" The demon only growled before saying, "H... He'll... B-Be... Back.." Tanjiro thought, "Who?" Unbeknownst to Tanjiro, the demon was also able to detect any presence that was close enough. Tanjiro looked at the scratch marks on the wooden pole and noticed it was close to breaking. The demon then lunged once more and destroyed the pole that held it back. Tanjiro was caught off guard and was scratched on the arm, shredding a piece of his haori off. He then grimaced but the demon took no pity and began to throw rapid punches at Tanjiro. Tanjiro blocked the punches while waiting for the right moment to strike back. The demon continued to punch but then kicked Tanjiro into the roof. Tanjiro thought, "This demon is smart!" He dropped down and said, "My turn!"

- Elsewhere -
A boy walked down a path with meat to feed his mother, who is now a demon. Unbeknownst to him, his mother is about to be killed by our main guy. He happily walked down the path to his house with still quite a ways to go.

- Back With The Battle -
Tanjiro cut the demon's arm off and next to its other arm. The demon screamed as it happened and was silenced by Tanjiro, who slashed its head clean off. Tanjiro then flicked his blade to the side to clean the blood and sheathed it back into the scabbard. He then thought, "I just hope the boy forgives me for the damage I caused to his shed." He then flew off, leaving a bit of evidence on who it was that killed the demon.

- About Ten Minutes Later -
The boy arrived at his house to place the meat inside the shed. He then saw a piece of ripped clothing that had a black and sea foam green checkered detail to it. He thought about it for a while and immediately took off to the shed. Once he arrived at the shed, he saw a destroyed pole and an untampered chain. The reason he had her chained up was that he didn't want her to escape and go get killed by the demon slayers. He then investigated further inside the shed. He found out that his mother tried to escape many times but finally did so. He looked up and saw a destroyed part of his ceiling. He walked outside and picked up Tanjiro's haori while saying, "She was the only one I had left! And you took her from me!" He took the piece of the Haori and took it inside. He cried himself to sleep that night.

- About a Week Later -
The boy couldn't handle the pain. He took a few things and ran outside with no destination in mind. Wherever his feet took him was no place good at all. After a few hours of nonstop running, he dropped to the ground and cried out loud. He then heard, "You poor thing... What's caused all this crying?" The boy looked up and saw another demon. It had a very long ponytail with red flames on its face. It also had a purple and black kimono. The most notable thing on the demon was that it had six eyes that read,

"Upper One."

The boy began to crawl back in fear. He was only used to the demon's (his mother's) kind attitude toward him. But this demon didn't look as if it was about to kill, but only ready to give. The boy still crawled back while Upper Moon One, Kokushibo, stepped closer. The boy yelled, "Before you kill me, please just turn me into a demon! I want to take revenge on the person who killed my mother! She was a demon but was killed by someone!" Upper Moon One asked, "You want to become a demon? Very well, if that man accepts you, you'll become a demon. I'll give you a certain amount of blood but don't even think about dropping a single drop." The boy didn't ask but watched as the demon slit its hand and has some blood splash into his hand. The boy was hesitant at first but drank all the blood that was given to him. He started to feel all the blood rush through his body and the pain. He didn't mind the pain but had one thought in his mind,

"I will kill whoever it was that killed you mother!"

- Storytime -
After a few weeks of devouring Demon Slayers and humans. The boy adopted the name Takeshi (Just another name I found, no meaning to it at all). He also somehow flew under the radar with his absorption and was mentioned quite a few times in the Corps. The only time he was mentioned was when Slayers were informed of a demon on the loose but quickly disappearing. The Slayers who were sent to defeat Takeshi were quickly dispatched and absorbed. Muzan took notice of Takeshi's growing power. He gave him a massive amount of blood and promoted him to the Upper Ranks. He was assigned to Upper-Rank Six before Hantengu and Gyokko were defeated, causing him to go to Upper-Rank Three. After being put into hiding, Takeshi couldn't wait to strike at the person (Tanjiro) who killed his mother. He still remembers that, while everything he's forgotten about.

Chapter 63.5: End.

Takeshi's abilities:
Takeshi is very smart when it comes to battle and can even outsmart Kinoe-ranked Slayers.

Blood Demon Art Abilities-
Absorption: Takeshi can absorb anyone and devour them whole if he were to do so. When he does that, he can mimic the people's moves that he absorbs.

Move Replication: Takeshi can almost mimic moves that are easy to do. After absorbing a person, he gains knowledge and can replicate their abilities (Water Breathing, stuff like that).

Strength Draining: Takeshi can drain one's strength if the fight prolongs for a certain amount of time, or if his gaze is put on a person for a certain amount of time.

Physical Abilities-
Body Manipulation: Takeshi can transform any part of his body into a weapon that he either sees or absorbed. He is also able to distort his body in weird ways to avoid getting cuts and slashes if he's fast enough.

And just like all demons, abnormally powerful physical constitution and accelerated regenerative abilities.

—

If you noticed, I made this demon for stealing moves and stuff so he can use it in the big battle that Muzan has planned.

Pretty clicheé story I know, but this is the best backstory I can come up with for any OC demon I thought of.

- A Little Secret -
Takeshi gained some of the Slayers' memories and searched for Tanjiro's look so he knows exactly who to look out for.

1488 words in total.