At a convention on digital currency, rarely does an audience Q&A session include a question as incendiary as, "Why is this fraud allowed to speak at this conference?" But that's how a discussion about bitcoin ended up last year in Seoul.

The supposed fraud is Craig Wright, an Australian-born technologist who gained notoriety three years ago when he declared himself the inventor of bitcoin.

The provocateur is Vitalik Buterin, a baby-faced Russian-Canadian programmer who helped create another popular digital currency called Ether. No one disputes Mr Buterin's role in Ether; many reject Mr Wright's claim to be Satoshi Nakamoto, the mysterious genius behind bitcoin.

Mr Wright is a comic-book supervillain for some in the world of cryptocurrency. Mr Buterin's rant was applauded by a handful of people at the conference, including one of the panellists and a man on the sidelines wearing a vest and metallic fibre shirt. It had the feel of an impromptu live performance of a Twitter flame war. The whole thing lasted 90 seconds. Footage recorded from the crowd provided an amusing YouTube video and sparked a fresh round of tweets mocking Mr Wright.

That appeared to be that, until a year later when Mr Buterin received a letter from Mr Wright's attorney. The legal notice, dated 12 April, said Mr Wright intends to sue Mr Buterin in the UK for defamation.

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Less than a week later, Mr Wright filed a lawsuit with similar claims against a podcaster named Peter McCormack, seeking £100,000 in damages. And on 2 May, Mr Wright's lawyers served Roger Ver, an early bitcoin investor, at a cryptocurrency meet-up in London.

Mr Ver said by email he intends to defend himself in court. Mr Buterin and Mr McCormack did not respond to requests for comment, but all three have recently posted messages online calling Mr Wright a fraud. In a blog post, Mr Buterin painted the legal dispute as being about censorship, free speech and truth.

Mr Wright has spent much of the last year with lawyers. He is currently defending against claims in a US court that he defrauded the estate of Dave Kleiman, a former business partner who died in 2013.

Mr Wright is accused of stealing bitcoins he and Mr Kleiman mined together about a decade ago. A federal judge ordered Mr Wright to submit documentation of his early bitcoin holdings, which were sealed on Monday, and he attended mediation on Tuesday in Florida.

At some point, he determined the courts could be a useful venue for achieving his own goals. Mr Wright, who says he holds a master's degree in law from Northumbria University in the UK, hopes a series of lawsuits can establish himself as the father of bitcoin. "This will give me the chance to prove my credentials in front of a judge, rather than being judged by Twitter," Mr Wright told Bloomberg in an email.

If he really is Satoshi Nakamoto, Mr Wright will have no trouble funding a protracted legal war on his critics. The true creator of bitcoin is estimated to hold about $9bn (£7bn) of the coins.

In most cases, the expensive prospect of getting sued tends to make rational people keep critical views to themselves. "There's some really broad recognition that the threat of defamation lawsuits really substantially chills speech," says David Greene, senior staff attorney at the Electronic Frontier Foundation, a civil liberties advocacy group.

For whatever reason, that did not occur here. Online discussion of Mr Wright reached a peak shortly after his lawsuit against Mr McCormack, and the content was overwhelmingly scathing. During the week following his suit, 65 per cent of posts expressed a negative sentiment, compared with about half before, according to Brand24, which monitors conversations on social media.

Crowdfunding efforts have popped up to assemble legal defence funds for some of Mr Wright's defendants. Data from Google suggests the litigation drew the most attention to Mr Wright since his contentious claims in 2016, when he offered what he called definitive proof of his role in creating bitcoin.

Although digital currencies have a market value of more than $280bn today, the circus surrounding Mr Wright shows that the industry still operates as a free-for-all. Experts are not entirely sure who conceived of the world's most valuable form of digital money, but there is enough of it to go around that the threat of costly lawsuits does not seem to deter anyone from speaking their mind.

John McAfee is a prime example. The software pioneer turned digital coin advocate says he knows the real Satoshi Nakamoto, and it is not Mr Wright. "I am going to tell the truth no matter what the consequences are," Mr McAfee said. "I've been sued over 200 times in my life. I am not afraid of getting sued." In response, Mr Wright called him "McScammer" and suggested they resolve their dispute in court.

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The cryptocurrency business is full of colourful characters. Mr Wright joined the starring cast in late 2015, when Wired magazine and Gizmodo reported that he and Mr Kleiman may have invented bitcoin. A few days later, Wired said Mr Wright may instead be "a brilliant hoaxer." Police raided his home in Australia as part of a tax investigation; he moved to Britain.

In May 2016, the BBC, the Economist and - most important in the eyes of bitcoin zealots - several prominent leaders of the cryptocurrency movement said Mr Wright furnished what appeared to be evidence of his claim to the throne. They said he gave a private demonstration of a special digital signature used by Satoshi Nakamoto. "The proof is conclusive, and I have no doubt that Craig Steven Wright is the person behind the bitcoin technology," Jon Matonis, founding director of the Bitcoin Foundation, wrote in a blog post at the time.

This did not quiet the doubters, either. "It would be like if I was trying to prove that I was George Washington and to do that, provided a photocopy of the Constitution and said, look, I have George Washington's signature," Peter Todd, a key bitcoin developer, told Vice's Motherboard.

Bitcoin holdings attributed to Satoshi Nakamoto have not moved in years, according to online ledgers. Critics have urged Mr Wright to verify his identity by transferring some coins, a proposal he has refused.

As Mr Wright spars with some cryptocurrency faithful, he is hoping to get the community's help with identifying his next legal target. He said he intends to sue an anonymous Twitter user known as Hodlonaut, whose profile picture is represented by a cartoon cat wearing a space helmet. Mr Wright posted a $5,000 reward for information to locate the person behind the account and referred bounty hunters to photos the user had posted showing arm tattoos. Hodlonaut wrote in a tweet on Monday that he had issued legal proceedings against Mr Wright in Norway.

Mr McCormack, the podcaster Mr Wright sued in April, is piling on as he awaits his day in court. He wrote a satirical response to Mr Wright's lawyers, saying, "I find it difficult to understand how I can affect the reputation of your client; this mistakenly states that he has any reputation left."

In addition to widespread derision, Mr Wright's crusade has inflicted damage on his business interests. He is now pushing a coin called Bitcoin SV, which he says is bitcoin the way Satoshi Nakamoto truly intended.

Mr Wright's lawsuits drew a harsh rebuke from Zhao Changpeng, the head of one of the world's largest cryptocurrency exchanges, Binance. Mr Zhao said he was "against fraud," and then Binance delisted bitcoin SV. The coin's market value plummeted 50 per cent over two days, though it recovered during the broader cryptocurrency rally in May.

Mr Wright and his few vocal allies are undeterred. On 21 May, Mr Wright said he was granted a US copyright for early bitcoin code and for the original whitepaper authored by Satoshi Nakamoto. Three days later, someone named Wei Liu filed a competing copyright claim. A spokesperson for the agency said it "does not investigate the truth of any statements made."

Calvin Ayre, a dot-com-era gambling tycoon and the most persistent supporter of Mr Wright, said he would release evidence proving Mr Wright's claim by the end of May. He did not. "But now that we have somebody challenging the copyright, we can take that to a legal conclusion, which is what we are now trying to do," Ed Pownall, a spokesperson for Mr Ayre, wrote in an email.

Mr Wright sees the insults as something more sinister than routine internet trolling. He says his detractors are criminals, who profit from human trafficking, and that their true motive is to sabotage his attempts to eliminate illegal uses of bitcoin. "I designed bitcoin to stop all of this," Mr Wright said. "That is why they hate me."