Marionette

"Balance is a bit of an issue, but I feel no pain." Captain is finally back up and moving around.
We've been camped behind the rubble for almost a full day, constant healing spells and health potions have done the trick of getting her almost back to her normal self. The stump where her arm used to be has been sealed cleanly, the skin smooth and pinkish at the end.
"H-how are you so calm about this?" Ranger's stutter resurfaces. His eyes keep darting to where Captain's arm should be, then quickly away again, as if looking might somehow be disrespectful.
"Just thought it's better than being dead," She laughs. "If this was back in our world, I could have made myself a robotic arm."
She staggers slightly as she walks towards me, taking a seat next to me. There's a thin sheen of sweat on her forehead despite the cool air, but her eyes are clear and focused.
"Besides, I heard someone else here went up in flames in order to take that thing down," She claps my back, the skin still raw, my armour on the ground around us.
"And I'm still feeling it, thank you." I grit my teeth. The burns across my back pulse with each heartbeat, a constant reminder of our narrow victory.
"What are we going to do about the next boss?" Retainer asks, helping Captain open a health potion. Her fingers work deftly to break the seal that Captain can't manage one-handed.
"Same as always, beat it." I say bluntly.
"I only use one sword, and I've still got my good arm." Captain flexes to prove her point. She rotates her shoulder with only a slight wince. "Not like I was ambidextrous anyway."
"But I still think we should wait a bit longer," Priestess suggests, the voice of reason. She glances at Captain's stump with professional concern. "Another day of healing would make a difference."
"As much as I would love to, I think we've overstayed our welcome here." I counter.
It's the truth. More and more enemies are somehow finding our small camp, and without
Captain setting up a proper safe zone camp, we're always at risk of attack. Just earlier, we had to fend off three waves of smaller creatures, each one larger than the last.
Now that she's up and about, we could get her to set it up, but at this point, it's most likely best to just move on.
"I agree, we should leave." Captain nods to me. "I don't know how effective a camp would be now, and the enemies could always just wait outside until we have to leave."
"Also, there's only a few more hours until a Guardian spawns." Ranger joins in, leaping down from the top of the rubble. He lands with barely a sound, adjusting his quiver.
Retainer appears beside me, also nodding in agreement. Her daggers gleam with fresh oil – she's been preparing while we talked.
"So it's settled then? Let's just go do this."

"Okay, quick gear check before we go in, everyone." I announce as we reach the door.
I grip my sword and shield tightly, feeling the new buff stones working inside them. The sword hums with a faint energy, its edge visibly sharper, while my shield feels lighter yet somehow more solid against my arm.
Varketh at least left us some good loot when he died. We all got a bunch of buff stones for our weapons. Sharpness for my sword, while a huge defense boost for my shield.
Ranger got increased accuracy, and the ingredients to create explosive arrow heads. He's already crafted a dozen, the arrowheads glowing with a dull red light in his quiver.
Priestess now has a large increase in her mana regen, so she won't have to rely on potions as much. The blue stone in her staff pulses gently, like a heartbeat.
Captain got a rare stone that increases her summon limit in boss rooms by one. A significant advantage considering her condition.
And Retainer got a stealth stone to make her harder to detect. When she stands still, I can actually see a slight blur around her edges, as if she's fading into the background.
Everyone gives a quick nod once they've finished their checks. Weapons drawn, potions accessible, armor secure.
"Alright everyone, we just fought a demon together. Whatever is behind here, should be a piece of cake."
They all give a cheer in agreement, the overall mood extremely high, and with good reason.
We just fought against what most people would call an impossible boss. And not only did we all survive, but we even took it out, we won.
I swing open the handle and make my way through the door.

The room is wide. Impossibly so. Grids on the floor, well lit. The ceiling disappears into darkness above, but the floor stretches out at least a hundred meters, marked with perfect squares like a giant chessboard. The air feels cold and still, carrying a faint metallic scent.
I feel something hit me from behind.
"You need to stop jumping into Boss Rooms." I admonish Retainer without even turning around.
"It was an accident?" Her questioning tone tells me it wasn't.
"What are we dealing with here?" Priestess asks, standing next to me. Her staff is already glowing, ready for whatever threat might emerge.
"Something I wished to avoid." I sigh loudly, lowering my stance.
"What are you doing?" Ranger asks in shock.
"It's okay. We're safe as long as we don't walk on that grid."
"Huh?" They all look confused.
"The worst boss in the game, it doesn't even have a name." I stretch. "This is less of a boss fight and more of blind luck."
"The goal is to make it to the other side of the room by walking along this grid, walk on the wrong square however and it's game over."
I gesture to Captain, and she understands what I want. One of her soldiers appears by us and begins walking towards the large grid. The spectral figure moves with mechanical precision, its translucent form catching the light.
"So, any in particular?" She asks.
"Pick any, one in ten chance." I state.
She shrugs and her soldier begins walking forward again, taking its first step onto A3.
Surprisingly, nothing happens to it. The soldier stands motionless, awaiting further commands.
"Should something happen by now?" Priestess asks.
"Yeah, if it was the wrong grid, then the boss would have killed it." That means. "Someone mark down which squares are safe."
Retainer pulls out her notepad and starts drawing a grid, writing down the first safe zone. Her pen moves quickly, mapping our potential path forward.
"Once we get three correct, I should be able to figure out the path, they don't have much in the way of variation. Once you stand on the safe square, the entire row becomes safe, so all of A is now fine to stand on."

Captain moves her soldier to the next square, but this time the ground starts to shake.
From above the grid, a large scythe swings down, impaling the soldier, ripping it off its feet before it fades away. The blade whistles through the air with frightening speed, leaving a trace of darkness in its wake.
Everyone stands there in shock, the reality of the price of failure a reminder that we are still in danger. Ranger instinctively nocks an arrow, while Priestess takes a step back.
"How is this boss fair?" Retainer whines.
"It's not, I knew a lot of people who would quit runs just because they encountered it." I tell her.
Captain has already summoned another soldier and sent it back to the grid, taking a different route than the first one. But just like the last, this one gets sent flying as well. This time the scythe cuts horizontally, slicing the soldier cleanly in half before it dissolves into motes of light.
This time though, the scythe doesn't retreat back into the ceiling. It hovers in midair, trembling slightly.
"No way, already?" I exclaim and a large figure drops onto the center of the grid.
It wears a black cloak, covering its entire body, its limbs twitch and move like it's being shocked, and the scythe it wields is fused to one of its wooden arms. The hood shrouds its face in darkness, but I can make out the faint gleam of eyes watching us, calculating our next move.
"No official name, but everyone called it Marionette."