When xxxMDMA arrived online in 2015, they were quick to market their product as top-rate. They offered free samples, inviting would-be customers to test a newly-created batch. They shipped orders within 24 hours. They provided top-notch customer service. Soon, business was booming.

Perhaps out of dark humor, or maybe out of actual sincerity, their biography page follows the crib note plot of Breaking Bad, the serial following one dying man's descent to evil after deciding to cook meth to support his family after he's gone. Whether it's true, or total lies, is impossible to tell:

"I am going to keep this as straightforward and simple as possible. The reason I am here, without revealing too much information about myself, is I need to make an additional large amount of money to pay for a very important and expensive medical procedure for someone very close to me."

Since xxxMDMA opened up shop on a handful of deep web marketplaces in 2015, the person behind the account has made at least $500,000 from fentanyl alone, according to an analysis by VICE News. The rapidly-growing demand for the powerful drug, often described as 100 times more powerful than morphine, has racked up a staggering death toll across North America in recent months.

The salesperson was prolific across a variety of marketplaces, accessible only through anonymized internet clients. They also sold, as their name implies, MDMA, as well as other niche designer drugs and guides on how to synthesize the compounds at home.

"This person is young and has a lot of life to live and the insurance companies do not care at allI. I will do whatever it takes to save this person. I am not asking for a handout or anything, I am asking that you give me a chance to show you that I have access to excellent substances and you will be helping me out in the process."

The vendor's recorded fentanyl sales on one darknet marketplace — just one of three where they maintained profiles — reveals that they have sold nearly 400 grams of the high-potent synthetic opiate, enough to make roughly a hundred thousand pills.

"I am a devout Christian and I never thought I would become a drug dealer and once I have earned enough money to help this person out I will no longer be a drug dealer. My guess is approximately 6-9 months as there are legal funds being raised for this cause as well."

The vendor disappeared suddenly in mid-June — true to their word, roughly seven months after they began — but xxxMDMA was hardly the first, nor the last.

***

Drug markets on the deep web aren't new.

Silk Road, the most infamous deep web marketplaces, was shut down in 2013. Its founder is serving a life sentence.

Since then, an assortment of would-be replacements have cropped up. Some are invite-only, some don't allow the sale of hard drugs, others afford vendors and buyers the luxury of using an escrow account to ensure that nobody gets ripped off.

They all shared three things in common: they employ advanced security measures to evade law enforcement, they all deal in virtually untraceable bitcoin, and they all use the public mail system.

A screenshot of a listing from xxxMDMA.

The marketplaces offer a cornucopia of illicit drugs, as well as stolen credit cards, hacking services, weapons, and, allegedly, hitman services — though investigations have failed to turn up proof that the murderer-for-hire schemes on the darknet are anything other than a scam.

But despite fears over the nefarious activities happening on the unregulated, virtually untraceable corner of the internet, the majority of the marketplace postings are for small amounts of marijuana, ecstasy, and cocaine.

Opioids like heroin and OxyContin are readily available on the sites, but fentanyl and other "RCs" — short for research chemicals, which usually include drugs that were developed but never meant for human consumption — have quickly found demand on the darkweb.

Since fentanyl first appeared on one popular market in November 2015, there have been nearly 1500 listings for fentanyl and other RCs.

The rise of the drug has mirrored a growing crisis across North America.

Statistics on the drug are spotty at best, as health agencies in America and Canada are only now trying to get a handle on the extent of the problem.

Percentage of Illicit Drug Deaths in Which Fentanyl Detected in British Columbia, from 2012 to May 31, 2016. (BC Coroners Office)

The Center for Disease Control reports that the death toll in Ohio alone jumped from 92 in 2013 to 514 just a year later — a 550% increase. The Kentucky Office of Drug Control Policy reports similar numbers: there were 121 deaths in 2014, and 420 in 2015. In that state, fentanyl is now to blame for a third of all drug deaths.

In Alberta, the provincial health authority reports that the death toll went from 66 in 2013 to 272 two years later. In neighboring British Columbia, fentanyl was implicated in 474 overdoses in 2015, and this year is proving to be even deadlier; near 190 overdose deaths have been reported in the first four months of the year, prompting the province to declare a state of emergency.

***

Scoring fentanyl is proving easier and easier as demand grows across the continent.

The fact that fentanyl is so concentrated and easy to transport, by powder, patch, pill, or liquid, makes it all the more attractive to would-be dealers or traffickers.

In Canada, significant quantities are coming into ports from China, as VICE News reported earlier this month, where the drug is not controlled by the government. Patches and pills, meanwhile, have been seized at Hells Angels clubhouses in Ontario, suggesting that the biker gang may be doing some of the domestic distribution.

VICE Canada went to the centre of the fentanyl epidemic to get a first-hand look at the effects of the drug, and how difficult it can be to get treatment for opiate addiction.

In the United States, speculation has focused on Mexican cartels as being the main pushers from the drug. The Drug Enforcement Agency suspect that the gangs have imported some from China, and made some in their own lab.

The darkweb, however, has also been moving significant quantities. What's more, it's underscored that the drug can be made relatively easily right here at home.

***

Whoever was behind xxxMDMA mostly did small-scale sales, obviously intended for personal use.

Their most popular product is 100mg of "99.8%+ pure" fentanyl, which runs for 0.2017 bitcoin ($140 USD). The online marketplace reports they've sold 730 units of that particular product between December 2015 to June 15, 2016. For $130, you can buy two fentanyl nasal sprays — which they bill as "by FAR the easiest and SAFEST way to use Fentanyl". The vendor has sold that particular item to 286 customers.

Each pill contains roughly four to five milligrams of the drug. Doctors say that two milligrams can be enough to kill the average person.

But the vendor also offered bulk sales. They listed 5,000mg of the drug for $5,000. If an enterprising dealer wanted to press that powder fentanyl into pills, the street value could be around $25,000.

The shadowy world of darknet marketplaces, a sphere that police and law enforcement agencies have long tried to crack with varying degrees of success, rely heavily on reputation and reviews.

Reviews for xxxMDMA were glowing. Over six months, he garnered thousands of positive reviews.

"Perfect. As Usual. Thanks Bud!" wrote one user who spent $1,100 on a gram of fentanyl.

"Overall great first experience. Stealth is the best ive had yet. Will be my go to vendor for sure," wrote another who spent $150 on fentanyl in early June. 'Stealth' is the steps the vendor takes to encrypt communications, disguise the packaging, vacuum seal the product, and is a coveted ability for darknet vendors.

Cutting a line of fentanyl. (Dopesick)

One reviewer lamented the high prices and the fact that xxxMDMA usually operated on a "finalize early" basis, meaning they would collect the money before the product had actually arrived. Nevertheless, wrote the reviewer, "good goddamn, if it isn't worth every penny. Never knew fent was supposed to be such beautiful, glistening crystals."

But the reviews shifted in mid-June. The prolific dealer had exit scammed.

In darknet lingo, exit scamming is when a vendor collects the bitcoin on a slew of sales, then never ships the product. It could happen if they're worried law enforcement is closing in, or if they've simply run out of product but want one last score.

"Never arrived. Now I am going through withdrawal. I wish I read the reviews and saw this was an exit scam. This vendor was such an awesome person. now he is ripping people off," wrote one user, out for $140, signing off with the universal symbolic of digital disappointment:

:(

One unfortunate buyer was taken for $37,500, according to the records on the online forum. "I just want to say you're welcome to the little girl I paid for her surgery. You suck at life. I hope Karma gets you were it counts!"

"Withdrawing and desperate," wrote another.

What made xxxMDMA special on the forums was that, as they themself repeatedly bragged, the product wasn't a poor quality Chinese knockoff. Whether or not the product really came "directly from the manufacturer in Europe," as advertised, is unclear, but review after review touted the strength and purity of xxxMDMA's fentanyl.

"This stuff almost killed me! I took a very small amount and spent the next 6 days in the hospital," one reviewer wrote.

In the last batches sent out by the vendor, however, users complained that they had received drugs other than what they ordered. Many reported receiving U-47700, a designer drug that can be dangerous in its own right, instead of fentanyl or ecstasy.

***

Drug marketplaces on the deep web attract a certain kind of user. They are concerned about quality, they provide feedback, they issue warnings about how to use products. In short, they are careful. They are particular.

Guides for fentanyl have been passed around the deep web, to help guard against overdoses. One Reddit user provided a clear step-by-step guide to stay alive, beginning with a warning to avoid the drug at all costs, capped off: "TL;DR Fentanyl is a dangerous drug but if you really have to play pharmaceutical Russian roulette the above might help dodge a bullet." Discussions even began around implementing price floors for fentanyl, in order to ensure that it was not being passed off as higher-priced, and less deadly, opiates like oxycodone.

A picture submitted by one vendor of fentanyl.

As one user noted: "Killing off your entire customer base is not economically viable."

But even on those generally permissive online communities, users frequently warn that fentanyl ought to be avoided.

Last month, one fentanyl vendor posted to Reddit that they would be exiting the business. "I broke the number one rule of dealing, I became addicted to my own product," they wrote.

"The withdrawal lasted about a week from start to finish," the post reads, as others joined in with their own stories. "I was screaming out in pain and I have never screamed in my life. I'm a very quiet person."

***

With xxxMDMA gone, quality fentanyl dealers on the dark web appear to be few and far inbetween.

One vendor, who lists their product as originating from Canada, has moved a few thousand dollars in fentanyl in the last few months, but has not sold nearly the same amount of product as xxxMDMA. But, unlike their erstwhile competitor, the Canadian vendor ships worldwide.

Another seller, based in the European Union, maintains good reviews but has only racked up a fraction of the sales of other vendors.

Ultimately, other vendors will come along. Doses, potency, and prices will fluctuate. But the dangers of the providing fentanyl, the drug that is burning like wildfire through high-risk communities, will continue.