Hey everyone! Sorry this one took so long. I've been focused on rebuilding the backbone of this crossover universe in The Girl Who Could Knock Out the Hulk over on AO3 (the FFN version is out of date until I catch up), for reasons that should become pretty apparent within the next couple chapters! I promise they won't take as long as this one, haha. Hope you enjoy!


It really should be more of a shock for Ben, finding a giant, beautiful underground city populated by thousands of Trolls of all shapes and sizes under his hometown, but his chosen 'career path', so to speak, has taught him that the wildly unexpected is, more often than not, actually the norm.

Giant, insectoid drones in service to a long-thought-dead alien warlord attacking Arcadia every other day? Sure. A high-tech wrist watch that allows him to turn into a member of pretty much any sapient species in the galaxy? Why not. A secret society of magical stone monsters allergic to sunlight living right under their feet for, presumably, hundreds of years? Really, he's just surprised Grandpa Max didn't somehow know about it already.

Even though, pressed for time as he is, Ben can't really stop to enjoy the scenery, he gets the whole tour as XLR8. Not that he'll remember much of it as a human - the human brain simply can't process the vast amounts of information a Kineceleran takes in - but he searches every nook and cranny of the massive cave system under Arcadia until he finds the battle. All in all, it takes about ten whole seconds - an exasperating amount of time for the speed demon he's taken the form of - to find the place.

In retrospect, he should've just looked for the armored Trolls anxiously pointing their spears and axes towards the shape-shifting arena.

He spots a six-armed Troll, trapped and struggling under an energy net, no doubt SixSix's doing. It's hard to tell in slow motion, but a couple other Trolls seem to be trying to pull the trap off him. It's a simple matter of jabbing at the tiny metal nodes projecting the net - Kineceleran bodies don't conduct electricity, else they would build lethal amounts of static - to destroy the pellets and free the captive Troll.

The guards growl at him, pointing their weapons at him. He taps the Omnitrix's emblem on his chest, shifting back to normal - not that it really makes the Trolls any less hostile. "Sorry for inviting myself in." -he says, nodding at the massive metal gate barring entry to the arena. "I'm just here to help my friends."

One of the Trolls helping the freed one up - a massive, turquoise-shaded beast adorned with thick, limestone-colored horns, crystalline forearm and back spikes, and a bronze-like prosthesis in place of his right arm - glowers at him. "How did you get into the city, fleshbag?" -he demands. His voice is deep, like stone rumbling in the depths.

Ben pulls up the Horngazel. "A doctor named Barbara Lake gave me this key." -he explains. "And another person named Claire asked her to. I think they might be in there, with my cousin and girlfriend?"

The Troll snatches the ambarine crystal away, claws that have worn away with time and use into something resembling nails still scratching his hand something fierce. "Stow your mistrust for this human for a moment, Draal." -the six-armed Troll chides. "We may discuss our home's safety and secrecy later - the alien interloper tarnishes our sacred arena, and so for now, we must join forces with this strange, shape-shifting boy."

Kevin comes in, panting. "Don't...forget...about me…" -he says, taking a moment to catch his breath. "Goddamn it, why do you guys need so many stairs?" -he mutters, meekly.

Draal huffs. "You're more than welcome to plummet to your death next time, human." -he grumbles, mildly amused. "And you, Blinky...how do we know these two aren't Changelings seeking to gain our favor? The short one's already demonstrated the ability to morph."

Kevin snickers at the barb. Ben tries to ignore it, on account of a) being unfortunately true, and b) finally getting a good look at the chaos on the other side of the gate. Once again, the Omnitrix chimes ready. "Listen, we can stand here and argue, or we can go in there and put a stop to SixSix's destruction. Figure out what to do about us after we beat the guy, ok?"

"A bit too valiant for someone who's just discovered Trolls exist." -Draal notes, towering above him. "For all you know, we punish trespassers by devouring them."

Ben rolls his eyes, pops the dial, and turns into Four Arms, the Omnitrix's sample of a Tetramand - and possibly his strongest current alien, a being powerful enough to maybe give the Hulk a run for his money. Four Arms' massive frame immediately eliminates the height difference - he is, in fact, a head taller than the now indignant Troll. "Tell you what, Tiny. We take care of this, and I'll let you try and take a bite."


Julie can't help but wonder what her parents would say if they saw her now. They're much less overbearing now, of course, but surely they'd object to their only daughter dodging laserfire from an alien bounty hunter.

To be fair, they wouldn't believe how well she's doing; hell, she's surprised by her own prowess, by the relative ease with which her body has adapted to life and death situations. It's not like SixSix has gotten any less deadly, either - the bounty hunter has made it abundantly clear that he has no qualms with employing deadly force - but somehow, without any training beyond her experience as an athlete, and the crash course on her gear provided by the Accuser's StarForce unit, she's managed to keep up with not just the alien, but the lethal arena shifting under her feet.

That being said - and judging by the massive axe that very nearly took her head clean off just now - she should probably stop musing in the middle of a fight. After narrowly avoiding the blade, she slides down a massive stone slab, and onto a platform that seems to be, at least temporarily, stable enough to stand on.

Claire leaps from a nearby ledge onto the same platform, rolling to a stop beside her. "We really need to quiet down the Forge." -she says to her. "An obstacle course may be good for training, but it's a bit much for a battlefield."

Julie couldn't agree more. "How do we stop it?"

The sorceress points at the large button SixSix originally shot. "Just have to push that thing again."

"What, that easy?" -Julie raises an eyebrow.

"Not while that guy's on overwatch." -Claire admits. Indeed, the bounty hunter's decided to perch atop the structure, right next to the Troll sculpture in the middle of the arena. He seems more or less content to watch them struggle to survive the shifting colosseum, but now that Julie has a moment to think about it, he does seem to be protecting the big stone button - sniping away at them every time they get too close, herding them away from the area with a volley of missiles and towards the deadly scythes and grinding gears.

"Got'cha...so, let's knock him off his pedestal." -she says. "Can you teleport me up there?"

Claire purses her lips. "Can you take him on long enough for me to sneak to the button?"

Julie chuckles. The legit answer is probably no, but they haven't gotten this far by being realistic about their chances. "Just get me to the top, Sabrina the Teenage Witch." -she teases.

Claire shakes her head. "I'm a sorceress, get it right!" -she complains, but swiftly extends her staff, and conjures a portal ahead of her. "Good luck, Julie."

She tilts her head, and runs inside the portal, quickly becoming immersed in what feels like night incarnate. There's a texture to it, a feel to the darkness like the air on a frigid winter storm - humid, biting, almost hostile. Her stay is all too brief, but she decides right then and there that she's not exactly eager to repeat the trip. Back in the real world, she's faced with the bounty hunter's back, so she doesn't stop her run, tackling the alien and sending them both careening off the edge.

SixSix growls, indignant, activating his suit's boosters to try and stabilize their fall, but Julie, thinking quickly, jabs her mechanical hand into one of the thrusters as hard as she can. Fortunately for her, the prosthetic's sensors are programmed to stop giving her nerve endings any feedback past a certain pain threshold, so she only feels a momentary sting as her hand is bathed in searing plasma. The metal holds, long enough for her to dig in deep, grab whatever delicate electronics she can, and yank them out.

Julie barely has enough time to let go before the jetpack explodes. She lands, hard, just a few feet below, rolling to a stop. SixSix crashes against the side of a giant axe, crumpling in a smoking heap some five yards ahead. Any hope that he'll stay down is quickly dashed, however; he growls, rising as he reaches behind his back and tears off the broken thruster pack, tossing it aside. "Wretched ape…" -he hisses, pulling a blaster from his thigh.

"Evangelion reject…" -she taunts back, rising to her feet. "You owe me an arm, asshole."

"Clearly, my mercy was wasted on you. Had I removed your head, you would not be here to complain." -he says. The bounty hunter taps his waist and two more hard light clones pop out, keeping watch for him while he treats her to his full attention. He chuckles cruelly, nodding at her singed but otherwise unharmed prosthetic. "Though what you bemoan is beyond me. That replacement is a marked improvement over your fragile, human form."

Julie yanks at the alien with her bracer - more accurately, a Kree Magnitron Gauntlet - pulling him toward her and right into a punch to the faceplate. "How's that for a 'thank you', jackass?"

SixSix recovers quickly, pointing her blaster pistol at her. She manages to put up her arm in defense, a couple of bolts bouncing off the Kree alloy, another burning away part of the ablative layer on her uniform as it hits her ribs. She charges recklessly, but SixSix sees it coming, effortlessly dodging and shooting her in the back. The suit takes the bolt, but any repeat impacts will reach her skin - which is decidedly not laser-proof.

"You are a child, wielding tools meant for warriors." -he mocks.

One of Claire's portals pops up behind the bounty hunter. "Y'know...there's a lot of that going around." -Julie smirks.

SixSix tilts his head, which gets summarily bonked by a massive crystal warhammer. The alien reels from the impact, his armor dented by the sheer power behind Toby's blow. SixSix's shoulder...blisters open up, revealing a pair of mounted blaster turrets, which track both of the teenaged heroes, forcing them to scatter as they deliver a withering torrent of blasterfire.

Julie manages to jump onto a rising platform, pulling her blaster from its holster and aiming down at SixSix. Unfortunately, the bounty hunter is quicker on the draw, launching a small, serrated disk that easily slices through her weapon, rendering it useless. She tosses the broken gun aside, cursing under her breath.

The arena shudders, then, reversing its motions and curling in on itself, like a flower in bloom watched in reverse - Claire finally pushed the button. The distance between them shrinking, SixSix leaps toward her, assisted by a series of small, maneuvering thrusters on his elbows and calves. Julie tosses herself backwards, narrowly avoiding the rising tackle, but this just leaves her prone, and thus perfectly positioned for him to pin her down, trapping her robotic arm under a smaller version of the energy trap he used to ambush their new Troll friend.

Julie grunts, bringing up her Magnitron Gauntlet to push the looming hunter away, but he expertly shoots the bracer off her hand. He seems to be savoring his kill. "The Kree arm won't make up for my jetpack...but it's a start." -he drawls. "I'm sure someone on Knowhere with a craving for Terran flesh will cover the rest."

The teen winces with disgust. "Gross, dude."

SixSix scoffs. "So flippant in the face of death. Perhaps you are more of a warrior than I thought." -he allows, the energy blade on his wrist sprouting into existence. For a moment, Julie is paralyzed with fear - it's hard not to immediately think of the last time she faced that weapon - but she manages to react quickly enough to mentally command her arm to detach from her body, rolling out of the blade's swing and onto her feet, even as the momentary imbalance leaves her a little wobbly.

"I am not dying today." -she defiantly states. "It's up to you whether you live to fight another day."

She can only imagine he's jeering under the helmet. "No weapons, no real training...no hope of defeating me." -the alien taunts. "There's a fine line between confidence and arrogance, human."

Julie would cross her arms, but she places her hand on her hip. "I guess you'd know."

On cue, the arena finally settles into a flat rotunda. SixSix is surrounded; the other teens have defeated his hard light clones, and stand now ready to take on him. The hunter surveys his opponents; Julie knows she's the weak link, but she's fairly confident Gwen or Claire could protect her before he could harm her. "So, what's it gonna be?"

SixSix primes his blaster, which is answer enough. "I'll take my chances."

Quick as lightning, he blasts at her. She hunkers down in place, but Gwen's got her covered, placing a magenta barrier before her. Frustrated, SixSix huffs, launching a couple of his serrated disks at the alien hybrid, but Claire opens a portal that sends them behind him, painfully carving into his already damaged back.

SixSix growls, and a couple of compartments on his thighs open, emitting a debilitating sonic blast that forces the teens to cover their ears. Gwen manages to power through, though, encircling the villain with her power and forcing him to endure his own attack, which immediately ceases. He pops out the energy blade again, which manages to cut through the barrier, and charges at Julie, but Toby manages to dash between them, blocking the wristbound sword with the shaft of his warhammer, which glows from the heat. SixSix reaches out and grabs Toby's forearm, electrifying his palm and zapping him away in a daze.

Fortunately, SixSix doesn't get the chance to reach her. Even as he dodges Claire's staff and tanks through Gwen's energy blasts, the massive gates to the arena open, and a large, roaring blur of crimson dashes past her and straight at SixSix, tackling and easily overpowering him. Four Arms sends the alien perilously close to the edge, only avoiding the fall by making quick use of his maneuvering thrusters. Kevin jogs in right behind him, bronze-skinned, followed by a sizable group of armed, angry Trolls.

Julie sighs in relief as Four Arms picks up her prosthetic and hands it to her. "Already got all the arms I need." -he says, giving her a dual wink.

She giggles, popping the arm back into its socket. "Five might be one too many." -she agrees. She looks back at the beaten hunter, whose armor is dented and sparking. "How are those chances looking now, jackass?"

SixSix pauses to ponder his options, not that he has many. He's outstayed the Trolls' welcome, more or less lost to a handful of teenagers, and gotten most of his gear wrecked, even before facing the quarry he's been hunting in the first place.

"It's either joining Krabb in the brig of a Kree warship, or finding out what Trolls do to someone who abuses their hospitality." -Julie says. "Your choice, SixSix. Either way, it's over."

The alien shakes his head. "It's not over yet, human." -he hisses. Suddenly, his whole frame shudders; the armored plates on the torso of his exosuit loosen, and two mechanical arms sprout at either side of his ribcage, each decked with mounted micro-missile launchers. His shoulder-mounted laser turrets and wrist-rocket launchers also pop out.

He levels his blasters. "Hand over the Omnitrix and I might let you live."

"Not really in a position to negotiate here, dude." -Kevin notes.

SixSix tilts his head. "Aren't I?" -he asks, rhetorically. "I can kill every last being in this room. Even if you somehow managed to overpower me, I would self-destruct and take you, and every lifeform in a ten mile radius down with me." -he threatens. Just for effect, the lights on his armor start pulsating, like a bomb counting down.

The thing is, they kinda saw this coming; neither the Kree nor S.W.O.R.D. had the most detailed of profiles on SixSix and Krabb, but they gave them what they could. Of Krabb, they said he was relentless and highly enhanced, but deeply abiding of the Hunter's Code - meaning he wouldn't target anyone beyond Ben, and he wouldn't strike until he was clear of any 'primitive' interference. SixSix was said to be a lot more...flexible, much more willing to get his hands dirty - but also very arrogant and vain, pathologically narcissistic. The only things SixSix has ever cared for - clearly demonstrated by his behavior thus far - are money and himself.

Meaning, he's bluffing - maybe not about the murder rampage, but definitely about the self-destruct. The bastard loves himself too much to go through with it. At least, Julie's pretty sure.

"Is he seriously pulling a Predator?" -she asks Four Arms, incredulous.

"He's definitely pulling a Predator." -her boyfriend shakes his head, disapprovingly.

Kevin brings up his Plumber's Badge, which promptly scans the villain. "Not very convincingly. He could at least pretend to overload his suit's reactor, maybe put out some radiation. He's not even cackling maniacally."

Toby sighs. "No respect for the classics."

"So...he's not gonna nuke Arcadia?" -Claire asks, tense.

Julie steps forth. "He isn't." -she says. "Can't really claim a bounty if he's dead. Can you, SixSix?" -she asks, turning to the alien.

"Dismiss me at your own peril, human." -he retorts, his tone clipped.

"Cut the crap, already. If you were really going through with this, the magic of Trollmarket would've banished you already. Right?" -she reasons, looking at Claire.

The sorceress ponders this for a moment. "...yeah, I...guess that's true."

SixSix tilts his head. His suit stops beeping. "...banished, you say?" -he asks, sounding entirely too gleeful.

Julie realizes her mistake a moment too late; being banished from Trollmarket would most likely put him back on the surface - and thus, free to escape and hunt them another day. Quicker than almost any of them can react, SixSix takes aim at the assembled citizens of Trollmarket.

Gwen steps forth, however, and Julie shudders, involuntarily - the redhead looks entirely fed up, a fearful sight from someone who's both incredibly powerful, and patient to a fault.

"Enough." -she says, her voice taking on an otherworldly echo.

The young sorceress closes her eyes, takes a deep breath, and becomes shrouded in a pink aura. Her eyes open, blazing magenta, and she rises above those assembled, her hair breaking free from its ponytail and billowing with non-existent air. SixSix, to his credit, fires everything he has at the Trolls while he still can, but Gwen seems to be, at least for the moment, above such a mundane offensive, easily casting a protective barrier over everyone else. Energy pools between her palms, and she unleashes a powerful blast of magical energy, striking the bounty hunter right in the chest, and well past the edge of the arena. Julie watches as the alien fruitlessly reaches for the edge, smoke and sparks pouring from his suit, and with a final, broken groan, falls off the Forge and into the murky abyss.

Everyone stares mutely at the edge as the violet glow filling the room subsides. Gwen floats back down, but her legs fail her as she lands, so Kevin promptly reaches out and steadies her.

Four Arms taps the symbol on his shoulder, turning back to Ben. "Aw, man, I didn't even get to show off Four Arms." -he laments.

Julie smirks, bumping shoulders with him. "Well, at least your entrance was good, babe."

Toby collapses his warhammer into its portable form. "I feel like we signed up for the hero course too early, Claire-Bear." -he says, shaking his head. "The younger ones got all the goodies."

Claire sighs. "They're definitely something." -she crosses her arms. "Though I don't know that I'd wish that fate on anyone, SixSix included."

Gwen pants. Her normally green irises glow magenta still, though Julie can tell that the magic is slowly receding. "W-what fate?"

Blinky steps forth, looking suitably spooked. "Beneath Trollmarket's foundation lies an unknowable void we call The Deep. No living soul knows exactly what may be found at the bottom - because none who've been sentenced to the abyss have ever returned." -he explains. "What little we do know leads us to believe it is far worse than the simple work of gravity, but rather a punishment fit for the worst among us. It is our harshest of punishments, only delivered a handful of times throughout the centuries."

"Unless SixSix somehow manages to boost those tiny thrusters of his before he reaches the threshold…" -Toby trails off. "Well, it's supposed to be a 'fate worse than death' kinda deal."


The Trolls attempt to convince them to stay for a feast, but Claire and Toby recommend against it - apparently, precious few Troll foods are even edible by human standards, and what little they might be able to eat is described as rancid, at best. Vendel declares them welcome to visit, even promising to craft them a (single) new Horngazel to use.

He does, however, ask that they refrain from terrorizing his people and wrecking their infrastructure in any future visits, which seems like a perfectly fair trade-off to the group.

"I can't believe there's so many of us in Arcadia." -Ben notes, as they climb the steps back to the surface. "Teenage superheroes, I mean."

"You don't know the half of it." -Claire says. "You know Zoe, the records store clerk?"

Kevin raises an eyebrow. He and Max used to visit the store, sometimes. "Pink-haired chick?"

Claire nods, though she seems a little miffed about his chosen descriptor. "She's a witch. She's been training me on the weekends. I'm sure she'd be willing to help us figure out your own magic, Gwen." -she suggests. "Though it kinda seems to me like you might be starting to do that yourself."

Gwen winces. "I wouldn't go that far. I wasn't really 'in control' back there. I just let loose and hoped for the best. Which didn't include murder, mind you." -she says, pursing her lips. "I didn't want to kill SixSix."

"Well, he definitely wanted to kill us." -Julie glowers, unconsciously rubbing at her artificial shoulder. "I say good riddance."

"He would've killed us and the Trolls if you hadn't stopped him." -Kevin argues. "You did what you had to, Gwen."

The redhead sighs. "Maybe...maybe I could've held back. I don't really know."

"Not that we advocate killing, but...in the moment, you do whatever it takes to get rid of the threat. Sometimes, that means death." -Claire muses.

"As long as you make sure it's not your death, I think you're good." -Toby shrugs.

"Then again, that's coming from us. We've been at this for a while, and we've...lost people, along the way. It's perfectly valid for you to feel upset. Probably healthier, if I'm honest." -Claire smirks, mirthlessly. Gwen gives her a similarly lacking smile.

The group finally reaches the small cavern on the other side of the canal's wall. "Well, here we are." -Claire says.

"Hey, you guys should give us a call next time you're dealing with one of those alien drone thingies! Our Trollhunter duties are kinda low maintenance these days, anyway." -Toby proposes. "Besides - and no offense - but you look like you could use a break."

"I, for one, totally agree." -Julie says, rolling her regular shoulder. "Assuming Hala doesn't immediately obliterate me for losing most of my gear, I need to restock and get some repairs done."

"Yeah, same." -Gwen admits, poking at her violet abdomen. "I can't exactly walk around with a glowing tummy."

Kevin wordlessly removes his t-shirt and hands it to Gwen, who smiles sweetly and ties it around her torso. Ben rolls his eyes at the domesticity, not that he can talk in that regard. He offers a handshake to Claire. "We'll call on you if we need help." -he promises. "And we'll help you if you need us, too. We need to watch out for each other."

Claire nods, and gets to work opening the portal. The light of the surface is blinding, even though the sun must be close to setting. The teenagers walk through the portal, and Claire seals the entrance behind them.

And then, they're surrounded.

A whirlwind of activity envelops them - half a dozen armored SUVs screech to a stop under the bridge, a couple dozen men in heavy tactical gear forming a perimeter around them. Above them, some kind of hovering aircraft casts a massive spotlight on them. Ben curses to himself - this has to be what Abigail warned him about. S.H.I.E.L.D. must've tracked them, maybe even watched them go through the portal. He glances back at Claire, who's somehow managed to make the Horngazel in her hand vanish without their noticing.

The troopers aren't pointing their weapons directly at them, but the fact that they have real guns is enough of a concern. He raises his hands, and the others follow suit. They could probably fight their way out of this, but chasing Stuart down and the fight with SixSix tired them out...and it's not exactly in their best interest to get on the bad side of an organization that probably has the Avengers on speed-dial.

A balding man in a perfectly pressed suit and sunglasses steps off the lead SUV. He looks unarmed, and somewhat unassuming, but Ben knows better than to dismiss him - after all, Grandpa Max doesn't exactly look like the astronaut adventurer he is.

He gives the teens a glance, and smiles to himself, then takes off the sunglasses. "Good afternoon. Phil Coulson, agent of S.H.I.E.L.D." -he introduces himself. The name sounds vaguely familiar to Ben. Judging by Kevin's widened eyes, he actually knows who this is. "Why don't you come with us? I'm sure we have lots to talk about."


This chapter was honestly really, really hard to make! I imagine it won't make everyone happy - I know I, for one, wish I'd come up with a better ending to the fight with SixSix - but trust me, this is the best version out of the many I scrapped during the painfully long process of writing this chapter. The next chapter will see the start of the last arc of this fic: S.H.I.E.L.D.'s intervention, the arrival of Vilgax, and the inevitable confrontation. It's gonna be pretty hectic! Make sure to tune in for that in the next few months.

Four Arms debuted this chapter, so here's his codex entry!:

The Omnitrix's sample of a Tetramand, from the planet Khoros. Four Arms is immensely strong, enough to give even the strongest species in the galaxy pause. His four eyes and four arms can function independently of each other; he can punch almost faster than the eye can see. Four Arms is one of Ben's favorite aliens; however, the Omnitrix rarely allows this transformation to take place, as it can be dangerously taxing on Ben's body and mind due to an odd quirk of Tetramand biology; this species is always in pain due to their continually self-improving muscles.

As always, thank you for your attention! Make sure to comment or message me if you have any questions about this story. Look me up on Twitter as Darthkvzn or Tumblr as darthkvznblogs if you'd like - and on Ko-fi, as Darthkvzn, if you like what I do and have a buck to spare.

Until next time!