Every living member of the police, military and Slayers Corporation around the world was facing rigorous training for the big day. You (assuming you were a civilian) could walk around the main vessel and not see a single frolicking member of the police force, military and the Corporation, not counting Kagaya, the Hashira, and Isekai.
Tanjiro stopped training to go grab a cup of cold water from the cafeteria and hang out in the break room. When he entered, he found Isekai, concentrating on something. "Hey, man, are you alright? You've been here for the past few hours concentrating really hard. Are you thinking about something?" he asked, concerned. Isekai then started to grimace a slight bit, his eyes twitching as he tried to regain his focus.
Then, out of nowhere, a purple energy figure appeared, constantly glitching. Isekai then flinched, causing the figure to disappear. He began to gasp, gathering his breath. "What's wrong?" Tanjiro asked, wondering what just happened. "I thought of a new technique I've been trying to properly use for the past few days. It involves the proper gauging of your body figure, your power, your focus, and abilities," Isekai explained.
"Well, how does it work?" Tanjiro asked, questioning the purpose behind Isekai's actions. "Supposedly, you're supposed to condense some magical power into a concentrated orb. I'll explain it later, I need to figure out how I can finish unsealing this ability..." Isekai explained, dismissing Tanjiro since he needed to find out how he could use it.
Isekai sat down, put himself into a meditation pose and began to focus once more. "Hey, Isekai? Are you there?" Tanjiro asked, waving his hand in front of his face. Then, in front of the focused lad was an orb, which had energy constantly seeping into it. "Woah, what's going on?" Tanjiro asked, attempting to touch it. Then, the concentrated energy transformed into a purple figure of Isekai, this time uncorrupted.
Isekai let go of his focus, and he coughed a bit. "Wow, I actually did it!" he exclaimed, proud of his new technique. "What is this?" Tanjiro asked, poking it. "That thing's my new technique. It does commands at my very own will and mind, and it doesn't use hubris!" Isekai explained. When Tanjiro asked how he spawned the energy figure, he explained in high detail.
"It works like this: You need to concentrate your energy, and focus it into one spot. After gathering enough energy, transform the energy into yourself, making an energy clone of you. It has minimal abilities, only being able to guard and attack, so use them wisely," Isekai explained. Tanjiro was quite confused, yet he understood what needed to be done. "But how did YOU do it?" he asked, crossing his arms.
"It's a difficult yet simple procedure. You focus some magical energy, and transform it into a figure of you that can do simple attacks and guard," he said, coughing. "I'll test this dummy out. Be on guard!" Isekai told Tanjiro, prompting the latter to go in defensively. The figure then began to attempt to punch Tanjiro, who was impressed that this felt the same as Isekai's punches. "This is actually cool!" he exclaimed, punching the figure, causing it to disappear.
"Here, I'll teach you the technique. Sit down," Isekai said, patting the chair. Tanjiro sat down, and crossed his legs. "Alright, good. Now, try to channel some of that sweet solar power you've been using these days," he instructed. "Now, gauge your own body figure by spreading this energy throughout your body."
"Focus the energy you spread back into the point, and then transmute it into your body figure," Isekai finished, crossing his arms. Within 10 seconds, a fiery orange figure of Tanjiro manifested before him. "Wow, you actually did it faster than me. Nice," Isekai complimented, poking the figure.
Power Mimic (The user concentrates their energy into one, and then disperses that energy throughout the body to gauge their own body figure. Color varies on used Magic. In Isekai's case, it's purple. In Tanjiro's case, it is orange. Their only abilities are being able to deploy energy shields, throw ranged punches, and work with other mimics to initiate large-scale attacks.)
"Hm... what say you and I have a quick, friendly matchup?" Isekai asks. Tanjiro perks up, and looks at him. "A fight? Uhm... okay, but where could we possibly fight without anyone disturbing us?" he asks, crossing his arms. "We got a suitable arena near the cafeteria. Let's hurry, we need to squeeze in as much time as we can training for the big day."
Isekai and Tanjiro enter the arena. It was a large space. "Head to the other end of the arena. We'll start in a bit," Isekai said, gesturing to the other starting point. Tanjiro walked over, and Isekai stretched. "You ready?" he asked, cracking his knuckles. "About as ready as I'll ever be..." Tanjiro replied, hopping up and down to limber himself.
In an instant, they both leapt at each other and began their duel. All that happened was them constantly blocking and throwing punches at each other, and that chain was broken when Isekai deployed a Power Mimic to shield him using Light Wall. After Tanjiro's planned heavy hit struck the shield, he was immediately countered by Isekai throwing a heavy punch. "He's still good as ever... Alright then, I'll start letting loose! Hinokami Kagura..." he muttered, chanting out as he leapt at his opponent. "Sunflower Thrust!" he finished, landing a piercing kick on his opponent's arm. The collateral damage penetrated his block, striking him in the face.
Sunflower Thrust (A thrusting attacking is performed. Using the legs or hands will inflict collateral damage.)
"You planned for me to block, didn't you?" Isekai asked rhetorically, deploying his double-edged spear. He swung four times at his adversary, then kicking him away with a strong hit. "Still more powerful as ever, huh- what?" Tanjiro asks, realizing that there were four clones surrounding Isekai, all of them having their arms in the air. He realizes what is happening as he looks up at the large sphere of energy above them.
"Nope! Stopping this one!" he says, charging up a Water Bomb. Isekai tried to stop him, but he deployed a mimic, who was on the defensive. It blocked every last blast he shot, and Tanjiro threw the bomb. Unfortunately, it was deflected away by him. "Now, go into eruption!" Isekai yells, slamming both his hands onto the ground, causing the ground beneath Tanjiro to give way, and a vertical wave of energy to hit him.
Isekai's mimics kept charging their power, and Tanjiro deployed a few mimics to try to cut down his opponent's mimics' attack to size. Soon enough, he broke out of the energy wave and began rapidly punching Isekai, to the point where has half-knocked out.
"Damn, you're good. Alright, let's stop here for the day," Isekai said, leaving the room. Tanjiro caught his breath, and followed him.
To be continued...