Since I kept putting it off... here, have a really long intro. 
---
"MaKinima-senpai! I thought this was supposed to be easy!"
A loud roar echoed through the volcanic caverns of the planet Amaduscia as Io protested, shouldering her bullet bow and racing behind a Cast nearly three times her size. Behind them was a Burn Draal, it's eyes filled with bloodlust and hatred as it chased down its prey, a massive darker seed on its back digging its tendrils into its flesh.
"Bwahahaha!" The cast laughed defiantly, unbothered by the dire situation they were in. "Now this is an adventure!"
"Idiot!" The smaller dewman girl screamed at the top of her lungs. "When you said we were helping Hi-En with a
little darker problem, you didn't tell me a Burn Draal was involved!"
"Do you not feel it Io-san!" The cast seemed to be totally ignorant of his partner's distress. "A great battle is upon us! It is what we ARKS live for!"
Plumes of black smoke surrounded them, giving birth the a swarm of Dagans that had begun to converge on their location.
"I'd appreciate it more if I could live to see the next day please!" Io shouted as she pulled her bow and readied it. The arrow shimmered brightly as it was charged with photon energy, then vanished as it was released by its wielder. In an instant, hundreds of thousands of arrows rained upon the cavern, piercing through the thick hides of the insectoid darkers.
"Nonsense little Io-san! As a good friend of Sukuna-hime once told me," MaKinima remarked jovially as the gigantic photon blade of his AIS Saber sliced through a crowd of Dagans ahead. "
'Don't sweat the small details!'"
"Ahh mou!!!" Io stopped and stamped on the ground in frustration. "Why are all my senpai a bunch of weirdos!!!"
"Aha! So we are going to face it head on now?" MaKinima remarked. Stopping almost dead on his heels, he reversed direction and began sprinting towards the gigantic dragon. His massive blade was drawn, and hummed softly as its photon blade fluttered to life. "OOOOOORRRRAAAAAAA!!!" He shouted, swinging his blade into the beast's forehead. The blade clashed against the Burn Draal's horn, failing to break it but sending the dragon crashing into the cavern wall with its immense force.
"Io! Now!" He called out to his partner, but she was already two steps ahead. In a flash, two arrows flew like beams of light into the stunned dragon. The first glittered brightly as it embedded itself into the thick hide. The second engulfed the dragon's upper body into a dark vortex of energy as it pierced into its scales. Then the first arrow suddenly exploded in a flash of light as it was triggered by the effects of the second. The dewman girl smirked confidently as she watched the infected dragon roar in pain. However, the moment did not last as the dragon quickly disappeared into the earth.
"Damn it." Io cursed under her breath. "That thing is fast--"
"Io!" MaKinima called out as he jumped to her position. The ground beneath Io's feet rumbled violently, and leaped just in time to avoid the beast bursting forth from the ground with a thunderous roar, it's hide armored in thick golden scales. It swiped its claws at her, attempting to swat the ARKS out of the sky while she was vulnerable. Its attempts were in vain as it struck against the flat of MaKinima's blade. However the impact was enough to send the cast flying into the nearby cavern wall with a violent crash.
"Senpai!" Io called out as her foot lashed out like a blade to strike the muzzle of the dragon to stop its momentum. She launched herself higher into the air as she fired another arrow, this time exploding violently in the dragon's nose and sending it crashing to the ground once more. Her fall now covered, Io hit the ground with a roll and readied another arrow. The Burn Draal would be focused on her now that her partner was out of the picture.
"I'm not done yet!" In that moment, MaKinima burst through the rubble and dashed to the dragon's rear. Raising the sword over his head, a wave of photon energy surged outward from his body. "ANCHOR HOWL!!!" He shouted at the top of his lungs as the wave smashed into dragon. His body glimmered as the resonance from his foe empowered him.
"What's up with the cheesy lines!?" Io commented in a slightly irritated tone, as the Draal turned its attention back to the greatsword-wielding cast.
"Is it not more heroic this way!?" Her partner remarked as he jumped out of the way of a fireball. "A hero should have their own special techniques!"
"I think you've been reading way too much manga!" Io retorted. A swarm of Darkers had now surrounded them, and they both readied their weapons as the Burn Draal roared and filled the cavern with a sea of flames.
---
"Uwaa... This is wonderful!" Franka clasped her hands together in delight as she looked a the gigantic chunks of Burn Draal meat that had been neatly packed into the campship's cargo hold. "I'm sure I'll be able to whip up something good to eat with this. This is even a rare species too, so the meat will have to be good! Thank you so much!!!"
"No problem." Both ARKS said in unison. However, compared to MaKinima's jolly voice prideful expression, Io's deadpan tone and slouched shoulders made it apparent that it had been no easy task. Her clothes were singed and tattered, and her pale skin was covered in ash and soot. Her partner wasn't in any better condition, but casts were built pretty tough.
"Another grand adventure!" MaKinima proclaimed proudly. "I couldn't have done it without your help Io-san!"
"No worries." Her reply was curt, and her tone gave away her exhaustion. "Now if you'll excuse me, I'm going to go home and take a bath."
"Very well." MaKinima acknowledged. "Rest is also important for the adventures ahead. I hope I can count on you again."
Io smirked, then bumped his metal torso with her fist. "Of course." She then stretched and started walking towards one of the transporters. "Just so you know, it's not like I'm worried about you or anything Senpai. But who else is gonna go on these suicidal missions with you?" And with that she disappeared behind the transporter doors, leaving MaKinima alone in the lobby.
"Hmm..." MaKinima rubbed the part of his head unit where his chin would have been. "What am I to do now...?" Franka had disappeared with some other ARKS personnel to help transport the Burn Draal meat, which now left him being the only one with nothing left to do.
"Attention! Briefing in five minutes! Please finalize your teams before departure!"
"Eh!?" The cast started looking around. He didn't exactly know what was going on, but usually ship-wide announcements meant that there were emergency quests occurring that required multiple ARKS working together.
In other words, a grand adventure.
"Glorious!" Makinima beamed. He could never pass up the chance for a good adventure, just like the heroes he had read about when he was a child. But he needed to find a group, and it seemed like many ARKS were already in their own groups and discussing battle plans. He scanned the crowd until he saw a small group of people standing off to the side. It seemed to only have two members, with a third--another cast--about to join. From the looks of their weapons they seemed be of the braver, gunner, and ranger classes. He decided that joining them would be a good idea. Unlike most Hunters who specialized in the Fury Stance disciplines, MaKinima had decided to specialize in learning the Guard Stance skills. It was odd of course, but to him he felt the most comfortable. Having been a bodyguard to Sukuna-hime for his entire life, it felt fitting to be the one to protect others.
And so, he walked over to the group.
"Greetings fellow ARKS! Might I join your party?"
---
I'm not really sure if I got Io's character correct, since I wasn't able to find too much about her online that was translated. So hopefully my interpretation of Io's character is correct.
