Legendary Shadow

The next day, Liam got ready and headed out to get some breakfast and went to the gym that was located on the island. When he got there, he saw a chunky looking man under a waterfall. He was all alone, which surprised Liam, normally gyms had at least two or more people there, but this guy was all alone sitting under a waterfall. 

Liam didn't see anyone else, so he summoned Mewtwo and told him to stop the waterfall. After he gave the order, Mewtwo tried for several minutes to wake up the gym leader but was ignored. Liam asked Mewtwo to use psychic to hold up the waterfall, but at the same time, he was struggling a bit which surprised Liam as he thought this waterfall must be extremely special if even Mewtwo was struggling to keep it up.

Chuck the gym leader and a specialist of fighting type Pokémon woke up right away when they felt the pressure disappear from his body. Chuck stared at the struggling Mewtwo in surprise as he said, "That's quite a strong Pokémon you've got there. I've never seen it before, but I know it's strong just from how it's able to lift this waterfall with his mind." 

Liam thanked Chuck and said he was here for a battle. Chuck nodded as he came from under the waterfall and headed to the stage. Mewtwo dropped the waterfall in relief as he slowly followed Liam onto the stage. Chuck sent out two poke balls and out came Poliwrath and Primeape. 

Chuck asked Liam who he would like to face first. Liam said both at the same time causing Chuck to raise an eyebrow as he said, "Interesting. Let's see if you can hold up your bark." Liam glanced at Mewtwo and told him he would fight both. Chuck laughed and said, "1 vs 2? You don't know anything about this world, but this will be a lesson for you." 

Then, they started the match. This was the first time Liam didn't have someone to officiate the gym battle on the side. They had no referees, just straight-up raw fighting. 

The two Pokémon charged towards Mewtwo. Seeing this Mewtwo floated up in the air and brought up a psychic barrier. 

Poliwrath noticed it and stopped right away while Primeape ran right into the psychic barrier causing a small bump on his face. He got angry and started punching it. His gloves started to shine as he closed his eyes and smashed right into the barrier, but the barrier did not break. It still held up, but Mewtwo flinched a little because that was quite a heavy hit. 

Chuck laughed heartily as he said, "Primeape, your weak sauce you can't even break a small barrier, go 100% on them and use rage." Primeape started to get angry as he was stomping his feet left and right while charging his energy. He turned a little red and then punched a barrier once again repeatedly until it broke. 

As soon as he broke it, a psycho cut came slicing through Primeape knocking him on his back. Primape got right back up surprising Mewtwo as he had used one of his most powerful attacks, and on top of that, it was a psychic move that should be weak against fighting types. 

Chuck laughed and said, "Primeape would have fainted after that attack, but I used the move Final Gambit." A strong fighting aura had erupted from Primeape as he turned burgundy red while his eyes turned completely white. Mewtwo was surprised by the power Primeape was emulating as he dodged the incoming attack from Primeape by sidestepping. 

Chuck was amused with this fight and started to get excited as he commanded Primeape to go all out while he secretly told Poliwrath to charge up a powerful attack for a good opportunity. Poliwrath nodded and started charging up his fighting and water energy to land a powerful blow on Mewtwo. 

Meanwhile, Mewtwo was dodging several attacks from Primeape as he had gotten stronger and was following Mewtwo everywhere he went but wasn't able to catch up because Mewtwo was using teleport while still attacking Primeape here and there using psychic attacks, However, it seemed like they were not effective against Primeape who had lost all kinds of reasoning and only saw his target and didn't feel any kind of pain. 

Liam was surprised with this battle because he didn't know that Primeapes could get that strong. Just when Primeape was about to catch Mewtwo, Mewtwo made several barriers while backing away from Primeape.  Primeape smashed right through the barriers and was just about to knock Mewtwo out when he disappeared once again using teleport. 

Primeape was extremely annoyed and got even angrier and more powerful as he disappeared from where he was standing. When Mewtwo saw this, he started looking around for Primeape but he sensed something coming so he teleported away as Primeape popped up from behind Mewtwo. As soon as Mewtwo disappeared, Primeape struck the air. 

Mewtwo thought he should have gotten tired, so he used psychic to get a hold of Primeape and tried to push him off the stage. As Mewtwo was concentrating on trying to hold on to Primeape, Poliwrath had come from a blind-spot and unleashed a powerful attack right at Mewtwo's ribs, blasting him away with a mega punch. 

Primeape had fainted from exhaustion making Poliwrath the only Pokémon left from Chuck's side. Mewtwo was injured from the attack, so he quickly used recovery to recover from the attack. Poliwrath was surprised by this and went to attack Mewtwo right away. He shot out a bunch of water guns and ice beams to freeze the barrier and break it. 

Mewtwo teleported out of the barrier and ended up behind Poliwrath as he grabbed Poliwrath and used Thunderbolt, shocking Poliwrath into unconsciousness making Liam the winner. Mewtwo was tired at this point and he went straight to his poke ball to rest. 

Chuck was laughing and clapping as he said, "Thanks for the great battle. I loved it. Please come again and here is your badge." Liam thanked Chuck for the battle and received the Storm Badge as he said his goodbyes and left. Liam went to the Pokémon Center to check Mewtwo in as he went to relax for the rest of the day.