Takes place during the paladin swap, before lotor's introduction.
Humans are sturdy beings, the champion proved that, the galra remember. So when the voltron's halfbreed crashes right on their doorstep, Shaken up but no worse for wear. The perfect specimen for the druids, for you see, Zarkon has been quite under the weather. Haggar takes advantage of the halfbreed's constitution, to revive her emperor.
How you ask? Simple, if the emperors body isn't well, give him a new one.
The little halfbreed's body isn't fit yet to house the emperor though, so haggar must encourage some changes, bring out his galra heratige, give him some bulk and strength, build up his quintessance endurance.
It towers over the druids in its chains, fur fighting scales for cover of its form, Tail like a beast of it's own lashes wildly with no where to go, the bright glow of refined quintessance shines within it's eyes, claws shear through the floor of its containment chamber where they are restrained down, any inteligence it once held is lost to a feral, wild madness.
The changes aren't perfect, but they are better then the start, the druids are satisfied. Time to test out its stability, endurance and strength...
They send the halfbreed to the arena, disoriented and barely coping with it's new appearance, it is forced to adapt and so it does.
Adaptations take longer then the druids hope for, but they improve over the phebes, the feral nature of the halfbreed is a bonus, it shall make the transfer of the emperor's conscienceness go easier.
The next step appears to fail against all careful calculation, The halfbreed rejects the emperor's conscienceness violently, awakening from the tranferance ritual and destroying it's restraints.
The druids are slaughtered, even Haggar is severly wounded before her escape.
The halfbreed has escaped.
Haggar takes some pleasure in knowing the mindless beast has lost the knowledge of piloting, the halfbreed is trapped on the planetside base, lost to the alien wilderness.
Haggar leaves with Zarkons wounded spirit essance stuff and her failed project rampages over the jungle planet's massive landscape.
She has back-ups that would take less effort then trying to break a mindless beast.
After Keith's disappearance the paladins are only able to recover the black lion (which has blacked out like it did when shiro disappeared) and his helmet.
They search for him of course, but have little luck, even Pidge's search through the galran database turns up nothing.
What they do find is Shiro! (or his clone...)
Maybe Shiro questions where keith is and they tell him of his disappearance and black's state. So Shiro tries black and fails and everyone is confused, but they blame it on the fact keith is blacks paladin now and not on the fact shiro has a weird new hairdo.
Over the next few months the search continues while clearing out the scattered galra army, then they get weird info from an abandoned druid lab (not the one keith was in)
Pidge recovers files from a project that appears to be creating a new Zarkon! Shock! Gasp!
They are still worried about keith but their hopes have signifigantly dropped by now and decide Zarkons return should be a higher priority then keith recovery. (thanks shiro clone, some brother figure you are)
It takes time but they find the encripted file that will lead to the planetside facility the druids used to ruin keiths life.(Takes like a week to decript and shiro is kinda a jerk the whole time saying its not important enough to focus on)
Pidge blows the whistle and everyone is gathered to the bridge where she reveals the coordinates that lead to the druids Zarkon recovery lab and they wormhole there!
The alteans insure the planet has few beast that will be of trouble to the paladins when they land, only like a dog sized cat weasel thing and some plants they shouldn't eat.
Hearing that the paladin trek onward becoming increasingly unnerved by the giant claw marks in the trees and huge weird paw prints (they are weird cause keith doesnt have paws, just distorted hands and feet)
They disregard their worry because of the cat weasel thing coran mentioned, that is until they find a dead weasel cat with huge claw tears threw its side (and keith sort of ate some of it, but leave him be he hungry)
Now more unerved and extremely worried as "nothing in this planets natural ecosystem should be able to do that..."
The paladins find the druids lab without running into the beast keith, that they don't know is beast keith.
And what they find inside is a lab half destroyed by keith and his monster claws that can somehow cut through metal walls, and some dead druids (which are just druid robes filled with dust) And that is enough for them to really be unsettled beyond the level they were before.
Pidge is adament about finding an undamaged console to gain info from while hunk is very very adament about leaving, lance close behind.
They end up finding a console and pidge discovers the project files, after some digging she discovers what the project really is and goes "Oh my god, they used one of their own to create a monster!?" because without images she doesnt consider it might be keith.
Oh yeah as uneasy as lance is he was still snooping around and comes in like "uuuh, guys...." holding up the black bayard, the one that wasnt recovered with the lion or keith's helmet.
And pidge has a "please god no" moment as she puts two and two together 'halfbreed' and 'experiment that left it completely feral'. She dig deeper into the files without telling the paladins her epiphany.
The others are kinda worried cause they now know keith may have been here a some point, here being a druid lab, with only druids...
A roar suddenly echos through the abandoned halls and the crew freaks, cause by then they have figured out that whatever the druids made it escaped and is now loose in the forest they just passed through.
----Keith's POV (may not be very clear cause he is all instinct)---
He could smell them, they returned, returned to the bad place that hurts, they are gonna make more hurt...
He stalked them, stalked them all the way to the bad place, but did not follow, could not return, never wished to return.
He slowly worked himself into a rage with his thoughts of pain and memories of torture and fighting in the arena and roared as he ran into the bad place.
Deciding that it was better to hurt them before they hurt him, his thoughts carried through his skull like voices directly to his brain, he could barely understand them sometimes, but he could understand the simple one.
Attack or Pain
He had found them in the worse place, they were in the place that had painful metal to hold him down and cold sharp metal that would freese his veins, his roar echoed painfully into his skull in the closed off space.
They had weapons, he did not understand them beyond the pain they could cause, his hackles raised to make himself look bigger to make them fear, to make them understand he would not return to the painful cold metal.
(like image him in this moment, hugs purple chimera of a galra, covered in dirt and filth with rags barely on his body, with solid glowing purple eyes, probably looks scary)
(insert battle here)
(he sees Shiro as the biggest threat because he is the biggest and his arm is the color of druid magic, so he and shiro wrestle luckily shiros are is stronger then the metal the base is made of cause he uses it to block keiths claws when he can)
(Hunk and lance are taking shots where they can to distract keith to protect shiro, but they dont do alot of damage cause the druids made keith more then just a mass of muscle)
(allura jumps in and out of the fray when she can to try and subdue keith before he hurts shiro, it does little more then feed keiths blind rage tho)
(Pidge on the other hand is conflicted, she is both horrified by how dangerous keith is and by how the thing before them might be keith, but she uses her brain and remembers the entire facility is a containment unit for keiths very strength and she gets a plan)
(after some deliberation and trying not to die by keiths claws they follow Pidge's plan to lure keith into a cell and lock him in, it works surprisingly easily and then they have their freak out about what keith is and what to do with him, cause pidge hasnt mentioned it might be keith)
(Shiro may or may not be betraying the team as haggar can see through him sometimes and knows they caught her "failed" project)
(Keith is extremely angry that he was captured and kinda expects to be hurt again like with the druids)
(End of battle)
---Next part is paladins POV and deliberation some more and shock about keith---