The call to attack came just after midnight.

“We call upon the nation’s righteous people to gather at 20:00 on the festive day of Mid Autumn Festival, for a grand crusade against our enemy,” reads a post on Di Ba’s Facebook page.

Di Ba is an online community, estimated to have more than 20 million members. They’re one arm of China’s troll army, ready to attack anyone who may have offended Chinese people in any way, flooding their social media pages with nasty messages.

Their target? A Swedish comedy host.

Jesper Rönndahl earned the ire of Chinese people after mocking them in a comedy segment, which was in turn produced after an incident involving Chinese tourists and Swedish police.

A Chinese family of three tried to check in to a hostel 14 hours early, and when told that they couldn’t, asked to stay in the lobby overnight. When hotel staff asked them to leave, they refused, and the police were called to remove them.

That incident set off a flood of criticism on either side. And then Rönndahl’s segment took things to a new level. His network, SVT, argued that it was satire. But China’s foreign ministry said that it was full of discrimination, and China’s embassy in Stockholm called it “outrageously insulting”.

That made Rönndahl, SVT and the Swedish Ministry for Foreign Affairs targets for Di Ba. Their pages were flooded with comments and memes from angry Chinese users.

SVT appears to have deleted many comments on its page. (Pictures: Facebook)

It’s not the first time Di Ba has struck out at what it sees as enemies of China.

In January 2016, Di Ba gained international fame after the attack on the Facebook page of Taiwan’s leader Tsai Ing-wen, flooding her posts with nearly 40,000 comments in just eight hours.

But the campaign against the Swedish program was organized by a much smaller arm of the community. While the original Di Ba was based on the online forum Tieba (operated by Baidu), this one, named “the Di Ba Central Army”, operates on Facebook, and only has more than 44,000 members.

3,000 to 5,000 people participated this time, an organizer claims. An administrator of the group did not respond to our request for an interview.

The Di Ba community started from an online forum created in 2004 about Chinese football player Li Yi. Li was constantly mocked by netizens because he compared himself to the famous French player Thierry Henry, who was dubbed as King Henry by his Chinese fans. So the Li Yi forum was given the nickname “Di Ba”, which loosely translates to “King forum”.

Over the years, the forum expanded their satirical interests widely in other issues, and has generated some of China’s most popular internet slang including “Diaosi”, a self-deprecating term for being a loser.

In its QQ chat group of nearly 900 people, members exchange their patriotic views, share VPN files and occasionally, someone asks when the next attack will happen.

Back home, Chinese netizens have mixed feelings about their troll campaigns. While some people are applauding, a lot of people also ridicule their behavior for being shallow, embarrassing and hurtful.

Some even joke it’s a good thing that they’re stuck inside China’s tightly-controlled internet.

“The Great Firewall was built to protect foreign internet users,” several users said on Weibo.