Note: this is Kid Goku from the Pilaf Saga
K.O. (OK K.O.! Let's Be Heroes) vs Kid Goku (Dragonball)
So now we got K.O. vs Kid Goku and since I know Goku like the back of my hand, I'll be going over him first:
Born as a saiyan named Kakarot on Planet Vegeta Goku was sent to Earth moments before his planet's destruction with one goal, to erase all human life. Once landed, an old man named Son Gohan found him and his ship deep in the woods and decided to adopt him and give him the name Son Goku. At first Goku was violent and a troubeled baby but after he fell from a cliff and hit his head, he lost all memories of his saiyan instincts and heritage and became a kind and loving boy. Soon into his childhood Gohan mysteriously died by some monster and Goku had to survive and never met any civilization until he met a girl named Bulma, who would lead him to an adventure for the dragonballs where he would make friends, meet strong teachers, and battle powerful enemies.
Goku has superhuman strength as he was seen crushing a boulder with his bare hands and threw Bulma's car all in the first episode giving him like small building level attack potency, he also tanked bullets to the face giving him superhuman durability. He also has superhuman speed as he was able to react to and tag a pterodactyl, which can reach up to 67 miles per hour, 29.95 meters per second. He has the ability of flight with his Flying Nimbus, a yellow cloud which can only be ridden by those who are pure of heart. He also has his magic power pole which can reach great lengths(it even went all the way up to the moon).
During his travels Goku met Master Roshi, his first teacher who he saw perform the Kamehameha Wave, a powerful blue beam of energy. When Roshi used he destroyed an entire mountain, and Goku copied him(showing that he can copy techniques just by observing them) but was only able to damage a car so Goku's Kamehameha at this time is only about wall level at most. Goku at this time hadn't yet recieved training from Master Roshi but he was taught by his Grandpa Gohan who was also a former student of Master Roshi so Goku still knows some martial arts. When it comes to intelligence, Goku's a dumbass but he's a genius when it come to fighting.
Goku's stamina is very high as can train for days with minimal rest.
Due to Goku's saiyan heritage he was born with a tail, and with that tail Goku can transform into a great ape by staring at a full moon. It was actually revealed that he was the one who killed Gohan but he was unaware of this and doesn't even know he can transform so in the midst of battle he would have to fall into looking at the moon. As a great ape he is easily large building level and the only way to stop him is by cutting off the tail, blowing up the moon, or outright killing him.
Some weaknesses are that Goku can be weakened and put into intense pain if his tail is grabbed or removed, and he only gets over this after the Red Ribbon Saga. He cannot fly without the Flying Nimbus in the beginning and as an Oozaru(great ape), he becomes a mindless berserker with no control over himself.
Now onto K.O.:
K.O. is an eager young boy who wishes to be one of the world's greatest heroes and to make his mom proud. K.O. is willing to learn anything that would make him a great hero, such as friendship. He is extremely loyal to Lakewood Plaza Turbo and is optimistic. K.O. has a strong willpower and courage, but is very naive. K.O. often shows that he want nothing more in the world than to help people, as it would help him to get closer to his goal of becoming a true hero, and because it feels good. According to Dendy and her data, she believes that K.O's desire to help others comes from a lack of father figure and want to gain love from others in order to fill that void despite having a loving and caring mother.
He has superhuman physical characteristics, energy projection, and sound manipulation. He has low stamina and around wall level durability as he was able to survive attacks that leave large craters in walls, though was badly damaged to the point he was unconscious, however this was early in the series and he has taken similar attacks with less damage, Dendy noted him as having "high pain tolerance".
He has around wall level attack potency as he was able to cause notable craters or even break holes in walls, despite being much weaker than Radicles and Enid as level 0.1, has still been able to fight against Darrell alongside them, has trouble breaking solid metal however.
He has low intelligence is his weaknesses are that he is allergic to peanuts and is sensitive.
His abilities are:
Power Fist Fireball: K.O.'s special move is the ability to shoot blue energy fists out from his fists.
Battle Cry: K.O. unleashes an ear-shattering yell that damages opponents. While only seen in the video game at first, he later shows that he can release powerful yells at Makayla.
So apparently this guy as a planet level feat, that is apparently an outlier, so here's why I guess:
Due to it being performed by one of the weakest characters in the verse so far, and being inconsistent with the many Wall level feats in the show. The planet busting feat in the intro is also overlooked as it was only for effect, and did not actually happen in the show.
Now that that's over let's get ready for the fight:
Since the arena was still undergoing repairs from the last fight, Goku and K.O. were taking this outside. They both stared each other down, waiting to make a move and both lunged at each other. When it came to hand to hand combat Goku was easily more skilled than K.O.. He blocked a punch from K.O. then swept under his feet and uppercutted him into the air. He jumped up and kicked K.O. back down to the ground, K.O. the got up and used his Power Fist to launched multiple energy fists at Goku. Goku managed to dodge some of them but got hit by a few and knocked to the ground. K.O. jumped up above Goku and Goku used his power pole to extend and hit K.O. in the stomach and launch him further in the air, Goku jumped above him and K.O. grabbed Goku by his tail and slammed him down to the ground. Goku weakly got up and decided to use his Kamehameha which K.O. was able to block with only a little damage. K.O. then kicked Goku in the face and grabbed his tail again and slammed him more and more. He kept slamming him, weakening him more. "N-Nimbus!" Goku called out as his flying cloud swept him up from K.O.. Goku was now on Nimbus flying and punching K.O., moving too fast for him. Goku was about to unleash another Kamehameha when K. out his Battle Cry. He screamed so loud Nimbus disappeared and made Goku's ears bleed. As Goku was covering his ears he took a quick glance at the sky and noticed it was now night out, little did he know this would change the entire course of the battle. Goku began to grow massively in size and grew sharp teeth and hair began to cover his entire body. Once finished his eyes were pure red and he stood several meters tall as the great Oozaru, and roared ferociously. K.O. barely dodged the oncoming huge punches and huge boulders being thrown at him. As a final resort, K.O. put all his remaining power into his Power Fists and launched multiple huge energy fists at Oozaru Goku and also even used his Battle Cry with all his might at the same time. Oozaru Goku however countered all of this with a powerful energy blast from his mouth and completely obliterated K.O.'s attacks and K.O. himself, leaving a huge crater. Oozaru Goku then roared and beat his chest as he stood victorious.
Yep, Goku wins and it was honestly was a really close fight. Goku had much higher stamina than K.O., was much more skilled in hand to hand combat, and had better feats overall. Goku's transformation to Oozaru made it an instant win as K.O. had no idea on what he needed to do and didn't actually have that much that could really finish Goku off that easily. Just know that any Goku after Pilaf Saga will beat K.O. with one finger like he did that one guy, just look it up.
So yeah, the winner is Kid Goku.
Next time on Battle Arena: Judy Hopps (Zootopia) vs Hellboy (Dark Horse Comics)