In the anime, Brock's Onix had really been done dirty.
Although Onix was introduced as a strong Pokemon at the start, he was never able to get more screen time and whenever he did, it was always a defeat.
It was only later on when Brock had left Onix with his brother, Forrest, that he was able to get stronger and he eventually evolved into Steelix too.
Later on, when Brock had returned in the alola arc, he and his Steelix had shown to master the art of mega evolution and Arthur still remembered the strength of a Mega Steelix that was shown in the anime.
'Considering all that, it makes sense that Brock's Onix is a blue aptitude Pokemon.'
Arthur thought about Onix's history that he remembers from the anime and gradually calmed the shock of Onix being a blue aptitude Pokemon.
After all, he can't be shaken up for too long.
He breathed slowly and calmed his beating heart down. Then, he thought about the prospect of Mankey defeating Onix and concluded that it was probably impossible.
Mankey was a reliable fighter, but even Arthur knew that it wouldn't be possible for him to defeat Onix.
In the first place, Arthur only wanted Mankey to defeat Geodude which he had done. His job was done here and anything after this was just an added bonus that he was thankful about.
"The second round of the battle will start now! Mankey vs Onix!!"
A loud shout came from the gym trainer that was acting as a referee and the second round of the gym battle started.
Brock was the first to make a move.
"Onix, use bind!"
The giant rock snake immediately moved towards Mankey with his tail aiming at Mankey's body. His large build shook the earth and boulders got smashed to bits if they came in the way of his tail.
"Mankey, jump on his body."
A giant Pokemon meant that there was a lot of space to attack and Arthur knew it well. He ordered Mankey to jump on top of Onix's body and climb through it.
It was easily possible due to Mankey's body which was suitable for climbing all sorts of places.
Mankey dodged the tail coming at him like a bullet and jumped on top of it. Then he made his way towards Onix's head.
His climbing speed was commendable and Onix shook his body, trying to throw Mankey on the ground, but he held on.
Just as the gym trainers thought that Arthur would easily win this battle too by using his unique tactics...
"Climbing Onix body is a good strategy, but you overestimated your tactics. Onix, use sandstorm!"
Brock suddenly spoke out loud.
"Wait... Mankey get out of there."
By the time Arthur realised what Brock was trying to do, it was already too late.
A large sandstorm brewed around Onix's body. No, the sand was getting released from the cracks in between the giant rocks. That sand and dirt came towards Mankey in an instant and it got harder to hold a grip.
Sand and dirt flew in Mankey's mouth as he struggled to hold a grip.
"Mankk..."
In the end, the sandstorm threw Mankey to the ground with a thud. He got smashed on the ground and a small crack appeared at the surface where he had fallen.
Mankey tried to get up, but there was a large bruise on his back and sand was all over his face, including his mouth.
He had clearly lost this battle.
"Mankey can't continue the battle. The winner is Onix!"
The gym trainer acting as a referee shouted and that was the end of the second round. All the gym trainers watching the battle cheered as Arthur called Mankey back to his pokeball.
"You did great. Now, take a rest!"
Arthur thanked Mankey and looked back at Onix.
The coordination between Brock and Onix clearly showed their experience battling together and Brock was only able to counter his strategy with sandstorm due to him knowing Onix really well.
He knew every strength and weakness of Onix and that was what made them so strong.
Arthur understood this well after experiencing it himself. He felt excited, knowing full well that was unlike any other battle he had faced before.
It was a gym battle and he was finally able to notice the difficulty of it.
"Charmamder, come out!"
He called out Charmander who let out a confident cry upon descending on the battlefield.
"Charr!"
"A fire type? Are you sure you want to use him?"
Brock said as he stared at Charmander.
He was pretty sure that Arthur was gonna use a water type against his rock type, and seeing a Charmander surprised him.
"Charmader is my starter Pokemon and also my strongest. I am pretty sure he can defeat your Onix." Arthur replied back with a confident tone.
"It's certainly an interesting choice. Let's see how strong he truly is."
Like that, the last round of the gym battle began.
Unlike before, Arthur went on the offensive from the start against Onix. He knew that being defensive was a foolish choice when Onix could just knock Charmander out with a whip of his tail.
"Flame burst."
A stream of fire directly aimed at Onix and Brock countered it with an equally powerful move.
"Dragon breath!"
A stream of pale, purple fire that resembled a dragon collide with the stream of fire and it created a large explosion, right in the middle of the air.
Boom!
A large amount of wind, which was a byproduct of the explosion, crashed everywhere in the gym.
It was a clear indication of the power that these two Pokemon held and the gym trainers couldn't help, but open their mouths in shock, wondering how strong Arthur's Charmander was.
They knew Onix's strength pretty well, but it was really rare for a Pokemon to be able to match it.
That's why it created a wave of anxiety and excitement between the gym trainers as they anticipated an amazing battle.
...
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