Here is a manga page from the previous chapter drawn by me. (It's pretty bad though)
For reference, here are the different Armament Haki stages:
Invisible armor:
-Allows the user to use their own spiritual energy to create an invisible armor around themselves, enhancing the user's offensive and defensive ability.
-Allows the user to injure logia devil fruit users.
Hardening:
-The user clads their desired body part with a black coating, making the said one become stronger in terms of both offense and defense.
Imbuement:
-The user can imbue their hardening onto any object they touch.
Emission:
-The user is capable of letting their power flow out from a part of their body and emitting it over a short distance.
-The user is able of harming people without a physical contact
Internal Destruction:
-The technique of emitting Haki in having it flow into a targets body and destroy it from the inside out.
Note: just because two people can use the same technique doesn't mean they're both equal, as we saw Garp and Chinjao can both use Hardening, but Garp's hardening is stronger than Chinjao's.
(Third Person POV),
When the fight started everyone was watching back on standby, nobody tried to interfere in fear for their life.
"This no longer a fight between two humans…" Kai was watching the fight in awe. He initially ordered his men to stop anyone from interfering, but that proved to be unnecessary.
"I don't' think this town can hold on any longer" Ayden stated.
"Forget the town, let's hope the island survives"
Somewhere on the battlefield,
Diana was taking care of the enemy using her sniping skills before she stumbled across a kid sitting calmly on a collapsed building.
When she noticed him, she approached him slowly "Huh?...Hey kid it's dangerous around here, you should go somewhere safe".
"Hoi onee-san, just mind your own business and move on" The kid replied in a rude way without paying any attention to her.
"Don't be like that kid, I'm just trying to help you" Diana looked genuinely worried about the kid, so she was tried to help him.
"Help me?...since you said that, how about you help find someone"
"Are you looking for your parents?"
"No, I'm looking for a taaall man with dark hair and big muscles" he tried using his hands to show her the exact height.
"I'm not sure, there are a lot of people with that description"
"Uuuum, I can't remember his name…wait a second" The kid opened his pouch and brought a piece of paper "Ahhh! His name is Calvin Helios!" he said showing Diana a wanted poster.
"?!!...Kid how do you know that person" At this point Diana started feeling something is wrong.
"Jason-sama asked me to take care of him, so can you help me find him?" The kid asked with an innocent look.
"Hey kid, who the hell are you?" Diana asked with a serious face.
"My name is Yamamoto…Yamamoto D. Tora"
[The sea near Yu Island],
"Rear Admiral Strawberry, we got reports stating that Ashen and Jason Willey have clashed" a Marine officer reported.
"Good, we will let them exhaust each other before we make our appearance" Strawberry was observing the island calmly while his ship was steadily approach it.
"The two families are also engaging with each other"
"We don't plan to interfere in the internal conflict, we are here for other matters"
"Pulupulupulupulu…Pulupulupulupulu…Pulupulupulupulu" Strawberry's den den mushi started ringing "Mushi mushi? This Rear Admiral Strawberry…"
"How is the mission going?" A deep voice spoke from the den den mushi.
"Everything is going according to the plan" Strawberry replied.
"Don't forget your priority"
"Yes, we will make sure to capture him at all costs"
"He is an important test subject after all"
"I understand Vice Admiral Sakazuki…*gotcha*"
(First Person POV),
"I acknowledge your strength kid, tell me your name" Jason asked me while he was standing in his place thoroughly in his hybrid form.
"Ashen" I replied composedly.
"I'll make sure to remember your name Ashen…After I send you to hell!" He shouted as he dashed at me at a high speed, trying to kneecap me. I hurriedly tried to leap backwards, but he managed to catch me using his trunk.
"Shit!" The moment he was about to strike me, I crossed both my Haki coated arms Infront of me to defend myself while hardening my body using Tekkai.
"HORA-ORA-ORA-ORA!!!" He sent a barrage of attacks towards me, they were very fast that they left an after image while they also carried a heavy weight.
I kept defending relentlessly without a stop 'His attacks are a lot stronger than before!...' I thought, as I was getting slowly pushed back.
"Enough!!" I roared as I shot flames from all the direction of my body.
"Useless, your flames aren't strong enough to hurt me!" he declared, while we both rushed toward each other again.
"WRAAAAAA!!!!" x2
*BAAAAAM* our fist clashing generated strong shockwaves around us. After that I quickly jumped back and used Geppo to fly.
"FIRE RAIN!!" I proceeded to cross both my arms in front of me and used both my hands to fire a torrent of deadly fire particles. But he managed to easily dodge them with his observation.
After that Jason proceeded to launch himself in the air towards me.
We kept exchanging blows without a clear winner. When I launched myself at him, I amassed flames into my fist, and proceeded to punch him in the stomach while releasing my flames at once.
"Aaaarrrrghhh!!..." Jason groaned in pain and threw some blood from his mouth, but proceeded to strike me down quickly, without giving me the proper time to react. He managed to take me by surprise and smashed my head to the ground.
*CRAASH* The ground beneath us was destroyed and replaced by a huge hole. Jason didn't stop there and took the opportunity to deliver another attack. He launched himself in the sky and came crashing down on my back.
"AAAHHH-" I immediately lost my conscious and collapsed on the ground.
'!!...Shit! I lost conscious for a moment right there' I was lying face down on the ground, while Jason was in front of me, about to smash my head with his feet 'if I can't hurt you from the outside, I'll destroy you from the inside!'.
"See you in t-*SWOOSH*" The moment his feet was about to touch my head, I used Soru to move behind him at super high speed.
"Rokushiki Ogi" I stretched both my arms in front of me while aiming my clenched fists at his back.
"What-!!"
"ROKUOGAN!!" I focused all my physical strength to launch a devastating shock wave from my knuckles. I tried to combine all the six techniques and merged them into one move.
*PUUUFF* The shock waves went right through his body causing internal injuries, it was enough to make him threw blood and tilt a little.
"B-Bastard…huff…What did you do?" He turned back to me with a furious look in his face, his eyes turned red, and he was holding his stomach from pain.
"Huff…I will destroy you from the inside!" I declared, then I proceeded to use the remaining strength I have and launched at him again.
At this point we were both very exhausted, so Jason also started leaving a lot of openings and letting his guard down much more often. I took those opportunities to strike him using Rokuogan until he was about to collapse.
"Hehehe, you've earned my respect, what an epic battle" We were standing Infront of each other without a move "Let's end it right now!"
The moment he said that I gathered flames around us creating a massive fire wall, preventing him from leaving. When he lunged at me, I gathered and launched my dense flames towards him, forcing him to leap to the side.
After that, I closed the distance between us, and with my Haki coated fist, I launched a barrage of punches at him, proceeded with a flame shot.
Jason looked shaken after that, so I took the opportunity to deal the last strike.
"Rokushiki Ogi… ROKUOGAN!!"
*PUUUFF* When he received the shock wave, he was standing silence for a moment before he collapsed on the ground without a move.