For anyone confused, Cahdok is the blue one and Gahdok is the red one. I know, it doesn't make any sense considering everything blue, including the Bohrok, of whom these two are queens, has a naming convention that begins with Ga-, but it's true.

No one ever talks about their third sibling, Bahdok, who decided to go into electrical engineering instead.

Ah yes, classic bonks. I'm not the greatest lore expert, so I'll let someone else handle the fine details, but the basic idea is these dinosaur looking blokes are in charge of the Bohrok, small, round little fellows that served as the antagonists to the Toa heroes in 2002, tasked with wiping the surface of the island of mata nui perfectly clean. They are not evil creatures, they were simply unleashed too early for the nefarious purposes of the makuta. I'll stop myself here, and let the proper lore experts take it from here.

Fun fact: the original designs were spider queens who carried the bohrok on their backs. Their presence, based on Faber's concept art, is outside of the matoran/bohrok "evolution"

Ding-ding-ding! Come get ya lore!

We're gonna do a deeper dive for this one.

Long ago, an ancient race of scientists known as the Great Beings set out to build a gigantic machine, The Great Spirit Robot. A colossal being containing a world of Matoran inside designed to explore the universe and study the societies of other species in order to reform the Great Beings' broken home. In order to better observe other planets the GSR had an interesting cloaking mechanism. The robot would plunge itself deep into a planet's ocean and then use Energized Protodermis to form fake islands and landmasses to cover any bits of it's body above the waves.

This camouflage system lead to one major issue. How was the giant robot to leave a planet with entire landmasses covering it's form? The answer: the Bohrok.

Matoran's natural life-cycle was a three stage process that the MU knew well. Matoran into Toa, Toa into Turaga. But there was a seldom spoken about fourth (and fifth) stage as well. If a Matoran of Light died of natural causes, their body would shapeshift into a strange bug-like form known as a Bohrok and teleported to a far off nest to be cared for by the Bahrag. Whenever the GSR was ready to leave a planet the Bahrag would command the Bohrok storms to the islands' surfaces to strip them of all vegetation, level their mountains, and run crevices and cracks through the ground. Loosening the entire islands' foundations so it could be easily broken as the GSR rose.

The Bahrag were two of the six gods (Cahdok, Gahdok, Artakha, Karzahni, Tren Krom, and Mata Nui) placed in charge of the Matoran Universe by the Great Beings. Their purpose was to lead and care for the Bohrok swarms, breeding Krana to power the machines and instructing them on what parts of the island to break. The Bahrag spent most of their time in deep slumber, and when awakened would spread to far parts of their lair to maintain the swarms.

Each possessed the powers of three Bohrok, and when nearby each other their powers massively increased. In addition they had intense telepathic abilities, able to mind control anyone wearing a Krana. This mind control had a lingering effect, and after his temporary corruption Toa Lewa became attuned to the Bahrag's hive mind.

The Bahrag's lair was locked by a door that required 48 Krana to open and guarded by six suits of Exo-Toa armor. Inside of this lair they not only bred Krana, but created the fifth stage of a Matoran lifecycle: the six Bohrok-Kal.

Fast forward 100,000 years to the 2002 BIONICLE story. On the island of Mata Nui, currently covering the GSR's face. The Toa had just defeated the villainous Makuta Teridax for the first time, but the dark lord had slipped away of his own accord. Using a sonic signal, Teridax awakened the Bohrok early, long before the island had been evacuated. These Bohrok rampaged across the island, destroying anything in their path and endangering the lives of the Matoran. The Toa went on a quest to uncover all 48 Krana and enter the Bahrag's lair to confront the queens. The Bahrag were confused as to why the Toa would interrupt their mission, after all both's goal was to awaken the Great Spirit, and soon battle ensued.

Eventually the six Toa combined their powers to create a Protodermis seal around the Bahrag, imprisoning them. However, the floor of the chamber soon collapsed dumping the Toa into Energized Protodermis. Our heroes emerged transformed into much more powerful Toa Nuva while the Bahrag remained trapped in their lair's depths. With the Bahrag gone Bohrok island wide began to shut down, and Matoran claimed them as their own service drones.

But the Bahrag had a contingency plan. The six Bohrok-Kal were independent of the queens, and when their masters' signals stopped they awoke (beginning the 2003 story.) The Bohrok-Kal stole the Toa Nuva's Nuva Symbols, the source of their elemental power, leaving our heroes nearly helpless. A race against the clock began, as the Bohrok-Kal tried to find the now collapsed and sealed-off chamber of their queens and the Toa Nuva collected

But the Bahrag had a contingency plan. The six Bohrok-Kal were independent of the queens, and when their masters' signals stopped they awoke (beginning the 2003 story.) The Bohrok-Kal stole the Toa Nuva's Nuva Symbols, the source of their elemental power, leaving our heroes nearly helpless. A race against the clock began, as the Bohrok-Kal tried to find the now collapsed and sealed-off chamber of their queens and the Toa Nuva collected new Masks of Power to combat the threat.

In the end the Toa Nuva reached the Bahrag just after the Bohrok-Kal and watched as they moved the Nuva Symbols toward the Nuva Cube that kept the queens locked away. At first it seemed they were too late, but Tahu had a plan (Mask of Time, failed) but also a backup-plan! The Toa focused on their Nuva Symbols and flooded their weak elemental powers back into the keys. The keys began to overload with Elemental Power and leeched back into the Kal who were holding them. The Kal felt this surge of power and quickly formed a new plan. They didn't need the queens! They didn't need the swarms! They didn't even need Mata Nui! With this power the six felt they could rule the universe themselves.

The Bahrag watched as their minions deserted them, and then got their just desserts. The Elemental Power was too much for the Kal to handle, and it overloaded their own powers. Each Kal's abilities turned on itself and they were quickly reduced to shreds. The Toa Nuva retrieved their symbols and the Bahrag remained imprisoned.

Months later (in the 2007 story) we finally met the Bahrag again. The Matoran and Rahi of Mata Nui had left the island, and the Toa Nuva had been informed that the Bohrok must clean the island for Mata Nui to awaken. The two titans and six heroes shared a brief conversation and apologies, and the queens were freed to finish their work.

Sometime after the BIONICLE story ended the Bahrag left the Bohrok nest and corpse of the GSR to integrate into the newly reformed Shperus Magna society.

If there ever was a "White Whale" (gosh, how that term has been misused in the LEGO collecting community online) for me in the BIONICLE theme, Cahdok and Gahdok were it. In 2002, I was feverishly anticipating the Exo-Toa set, unaware of the role the suits would play in battling the rulers of the Bohrok. With the onslaught of Attack of the Clones merchandise in April, my budget for BIONICLE sets was wearing thin by July. I just barely managed to snag the Boxor set after getting the Exo-Toa at the end of June. The BIONICLE comic for July 2002, "What Lurks Below" fully unleashed the Bahrag twins, and I realized that it would be cool to have them in my collection. In those days, Wal-Mart would still discount LEGO heavily after enough time had passed, so I decided to wait.

My first missed opportunity was for my birthday in October that same year. The Toa Nuva had been widely released, so I was on the hunt to collect as many of them as I could for my birthday. However, BIONICLE sets from the year before were on clearance, specifically a large wall of shelves filled with Kanohi mask packs for something like less than a dollar a box. I went wild in grabbing as much as I could within my budget as well as a Lewa Nuva as well. My dad and uncle accompanied me on this birthday trip to Wal-mart, and interestingly enough, my uncle noticed one of the Cahdok and Gahdok sets and wondered if I'd be interested in getting that instead. Foolishly, I turned him down since it wasn't on sale. I figured I had more time.

The year ended and I completely both my Toa Nuva and Bohrok collections. With the advent of 2003 and the story of the Bohrok Kal's quest to find and free the Bahrag after their defeat at the hands of the Toa Nuva, I began my quest to obtain the monsters in earnest. At the start of February, on the day the space shuttle Colombia exploded overhead, my dad and I went to Wal-mart just to grab a few things. I rushed over to the LEGO aisle, hoping to find the Bahrag on sale. They still were not! Disappointed, I rejoined my dad and we went home. The next time I went to Wal-mart, the Bahrag sets were gone.

For years, missing out on that set haunted me. It bore the same hallmarks of Technic design that the Rahi sets of 2001 had, but managed to bring some interesting new parts to use like the click joints and Bohrok pieces in new colors. After 2002, large BIONICLE sets became simpler. More affordable and still fun to play with, but simpler by far. It would remain that way until 2008 with the introduction of large-scale vehicles for the BIONICLE figures to ride. But I needed my Bahrag!

In college, I joined eBay and started scouring the site regularly for LEGO sets I missed out on in earlier years. Cahdok and Gahdok were always on the shortlist for acquisition, but I was not successful until late 2009 when I at last scored a New-in-Opened-Box condition set. It took so long because being one of the larger BIONICLE sets, it's price had inflated well over $100 several years after its retirement. I wanted to nab it for less than $100. Auctions could be heated, and I know lost out on one at least once. Finally, I tried a search tactic that landed me the winning auction: since the set's release, retailers and toy shop owners alike had been reading the name of the set off the box as "CahOOk and GahOOk". I didn't understand back in 2002 and 2003 why this happened until I stared at the box long enough and realized the font made the "D" look like an "O". Realizing this, I would search for the set on eBay not just under the set number or the proper name, but under this silly misspelling. I reasoned the misspelled version might fly under most bidders' radar, and ensure the likelihood of me winning the auction with a lower max bid. Indeed, this happened, and I got the set for $88! After 7 years, it was a joyous moment!

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I eventually got the set home and built it several years later. It's great fun and they are both great to display together with those toothy grins. And although the build process is repetitive (both are identical aside from color and head decoration), it went together quickly for me and I was having those two snapping at each other in no time! They are now disassembled again and back in the box, but I feel like it was all honestly worth the wait.

P.S. Take all lore postings with a grain of salt. Some of the information presented in this RSotD post seems to have some added "flavor" that I don't think was proper canon at the time of BIONICLE's release (2001 - 2010). Nothing major, but some examples would be the status of the Bahrag as "gods" on par with Tren Krom and Mata Nui (the Bahrag served Mata Nui!) or the Bohrok Kal being the "fifth stage" of a Matoran of Light's evolution (they were created by the Bahrag as a contingency plan from regular Bohrok. So, less "evolution" and more "specialized mutation").

White. Friction. Axle. Pins.

I got two copies of this set and built all three models (Cahdok, Gahdok, and the combined model), but the thing I cared about more than anything else was white friction axle-pins. White 2L axles were pretty cool, too.

Ooooh, dang! Bionicles that kinda look like they're made from LEGO and are wonderful for it.

They wouldn't look out of place in Jurassic World or under Jabba's throne room!

Technic robot dinosaurs?

Heh, I had these as a kid, the highlight of my Bionicle collection really. They have quite a menacing look and yet a really detailed function with some cool play features. I thought the function was comparable to the Muaka / Kane Ra sets from the photos, but then I only managed to get those a decade later and realized the Bahrag's mechanics were quite different and IMO better. 2002 was really the best year where Bionicle mixed function with looks, and the Bahrag models really sold that, although not quite as posable as future Titan sets. And man did they have a ton of great parts, from the white technic axels used for the teeth to the various red and blue connectors and Bohrok shields and all that. Great sets.

Granted, the characters are less impressive in the story, but the reveal of the Bahrag in the 2002 comics really blew my mind as a kid. They looked properly menacing as the big bads of the year.

@TheOtherMike:
But that’s really a common thread to all Bionicle sets, at least for the first few years. Toa were designed to fight Toa, Rahi were designed to fight the Rahi they were paired with, or their combined form, and so on. Nothing was really designed to fight outside its class. The Manas, arguably the most powerful Rahi, couldn’t do more than kneecap a Toa that wasn’t knocked down first. The only real exception to this was the original Pohatu, who was designed to kick a rock. He was vulnerable to other Toa attacks, but not particularly capable of delivering in kind.

Those are some large comments.

It is a real shame we don't get this kinds of Technic sets anymore... I mean come on, there is so much you can do with the LEGO Technic system besides just vehicles, and this set is proof of that.

@LegoDavid said:
"It is a real shame we don't get this kinds of Technic sets anymore... I mean come on, there is so much you can do with the LEGO Technic system besides just vehicles, and this set is proof of that."

^This!

@ThatBionicleGuy:
There used to be a really short time limit, such that by the time you read an article and the comments, you were usually past the point where posts would stick. Huw increased the time limit, which I think is about one hour now. If you're not posting pretty quick, you'll want to learn to copy your entire post before hitting the Submit button. If it doesn't show up, just refresh the page, paste your comment in the box, and hit the button.

If you're going to make long posts, they also cut off at some point (but not in a way that's obvious while you're typing), so again, it can be a good idea to copy everything before you submit. If the post shows up, but it's cut off, you can hit the edit button, trim the bottom of your post, save the edit, and then paste the entire post in the text box where you can delete the part that already posted.