In the first three installments of this series, we looked at the crushing demands placed on idols. We also examined the suicides that those pressures can provoke. Additionally, we explored the scandal‑fueled cancel culture that can end careers overnight. Yet another force wears down entertainers in Japan and Korea: toxic fandom. This episode explores the darker side of fan culture, from stalkers and “sasaeng” intrusions to violent attacks and information leaks. These stories show how devotion can mutate into obsession – and the urgent need for better protection for performers.

What Is a Sasaeng?

In South Korea, obsessive fans who stalk idols are known as sasaeng (사생, literally “private life”). They view entertainers as possessions rather than people. They follow them to dormitories, restaurants, and airports. These fans also harass them with incessant phone calls. Companies often tolerate some level of enthusiastic engagement because fandom fuels sales and streaming. Nevertheless, the boundary between passionate support and criminal behavior is easily crossed.

Toxic fan behaviour is not limited to Korea. In Japan, fans have been known to physically assault performers or track their movements with GPS devices. Across both countries, stalkers justify their actions by claiming to “love” their idols. However, these invasions put artists’ mental and physical well-being at risk.

South Korea: Sasaengs, Anti‑Fans and Stalkers

Stalking the Stars

• Enhypen Dorm Break‑In (July 2025) – South Korean boy band ENHYPEN’s agency, BELIFT LAB, reported an unsettling event. A group of fans illegally entered the group’s dormitory. These fans even filmed the band members without their knowledge. The agency stated that the intruders were arrested on the spot and were under investigation for housebreaking and stalking crimes. In a public statement, the company said it was pursuing legal action. They aimed to target people who shared the group’s private information online. Meanwhile, fans demanded stricter protections.

• NewJeans Dorm Intrusion (December 2023) – A 20‑year‑old male stalker repeatedly broke into the former dorm of girl group NewJeans. This happened in December 2023. According to reports, he stole banners and hangers and posted photos of them online. In July 2025, the Seoul Western District Court fined him ₩10 million (~US$7,600). He had expressed remorse. The court noted that the group was no longer living there. It also noted that he had no prior convictions.

• BTS Flight‑Information Leak (July 2025) – Straits Times reported that three individuals were referred to prosecutors. Among them was an airline employee. They were accused of selling BTS’s flight details to “sasaeng” fans. The employees allegedly leaked information to allow fans to board the same flights as the band. They reportedly earned tens of millions of won from this. HYBE, BTS’s agency, set up a task force and cooperated with police to stop such leaks.

Violent Anti‑Fan Incidents

• Poisoned Drink (October 2006) – During a television rehearsal, a woman approached TVXQ member Yunho (U‑know). She described herself as an anti‑fan and offered him a carton of orange juice. The juice was laced with glue. Yunho drank the contaminated juice, began vomiting and was hospitalised. The woman later turned herself in to the police and admitted she wanted to “mess with” him. He recovered physically but described being traumatised by the incident.

• A.C.E Vehicle Sabotage (February 2020) – Beat Interactive announced that someone had tampered with the van used by the K-pop group A.C.E., applying super glue to critical parts. This act rendered the vehicle unable to function properly. The agency said the unknown perpetrator intended to cause harm. The group members required counselling due to anxiety. They pledged to adjust schedules and cooperate with authorities.

New Laws to Combat Stalking

South Korea responded to escalating stalking cases by introducing the Stalking Punishment Act. Passed by the National Assembly in March 2021, the law became effective from 21 October 2021. It allows courts to sentence stalkers to prison for up to three years. Alternatively, they can impose a fine of up to 30 million won. If a weapon is used, the sentence increases to up to five years or a 50-million-won fine. This statute marked a shift from treating stalking as a minor misdemeanour to a criminal offence. It also broadened the definition of stalking to include online harassment and the distribution of personal information. Despite this legislation, enforcement can be inconsistent; agencies still frequently urge fans not to harass performers and promise “zero‑tolerance” policies.

Japan: Fan Violence and Legal Reforms

Handshake Event Attack (2014)

In the aftermath of the attack, AKB48 temporarily canceled handshake events. They implemented stricter security measures, including the use of metal detectors. Kawaei eventually left the group, citing trauma and her inability to continue participating in fan interaction events.

On 25 May 2014 a 24‑year‑old man with a handsaw attacked members Rina Kawaei andAnna Iriyama of AKB48 and a staffer during a handshake event in Iwate Prefecture. The victims suffered bone fractures and deep cuts and required surgery.

In the aftermath, AKB48 canceled handshake events temporarily and introduced metal detectors and stricter security. Kawaei later left the group, citing trauma and an inability to attend fan events.

The Mayu Tomita Stabbing ( 2016)

Singer Mayu Tomita was stabbed more than twenty times by a fan outside a concert in Koganei, Tokyo, after she reported receiving hundreds of threatening messages. Although she survived, she sustained life-altering injuries and developed severe PTSD. The attack occurred because the fan was enraged after she rejected his gift.

In 2019 she sued the Tokyo Metropolitan Police for failing to protect her; the case concluded with a settlement in 2025. Public outrage over her attack prompted Japan to amend its anti‑stalking laws to explicitly cover harassment on social media.

Anti‑Stalking Law Reform

Japan bolstered its response to online abuse following the 2020 suicide of wrestler Hana Kimura. She was targeted by hateful comments on social media. In 2022, the Diet passed a bill to strengthen penalties for online insults. These offences are now punishable by up to one year in prison. The bill also imposes a maximum fine of ¥300,000 (about US$2,500). This is a significant increase from the previous maximum punishment of 30 days in jail and a ¥10,000 fine. The amendment came after Kimura’s mother campaigned for tougher penalties. The law aims to deter cyberbullying, although critics worry about chilling free speech.

Continuing Threats

Even with stricter laws, assaults on entertainers persist. In 2025, the Asahi Shimbun reported that Tokyo police agreed to pay compensation to Mayu Tomita. They admitted to mishandling her reports of stalking and acknowledged systemic failures. Meanwhile, Japanese agencies continue to grapple with balancing fan engagement with artist safety.

When Marketing Fuels Obsession

Idol agencies do not only gain from fans’ devotion. They also actively cultivate para-social intimacy. This is done through marketing campaigns that blur the line between fantasy and reality. In 2011 AKB48 launched AKB Official Net, an internet service that offered subscribers special perks. One controversial feature, called AKBaby, allowed users to upload their photos. It generated an image of a hypothetical baby with their favourite AKB48 member.

The homepage even featured idol Yuko Oshima asking, “Would you have a baby with me?”. Membership costs ¥1,480 per month and includes an @akb48.ne.jp email address so fans can communicate with each other.

Another blog covering the launch noted that AKBaby was marketed with the slogan “Why don’t we make a baby? On the net.”. Such promotions invited fans to imagine romantic ties with idols. They also encouraged the belief in familial connections. This reinforced the idea that performers were emotionally available to them. While campaigns like AKBaby were meant to be playful, they exemplify the commercialization of idol culture. This can encourage obsessive attachments. These marketing tactics, when mixed with handshakes, virtual dates, and personalised messages, create a sense of entitlement. A minority of fans feel they have personal access. Sometimes, this has dangerous consequences.

Idol marketing often commodifies communication itself. Dedicated fan platforms like Dear U bubble, Weverse, and other K‑pop apps offer monthly subscriptions. Fans pay for the privilege of receiving one-to-many messages from their favourite idols. A Korea Times report noted that bubble charges about ₩4,500 (≈US$3.37) per month for a one‑on‑one messaging service and, as of late 2023, had around 2.3 million subscribers, while HYBE’s Weverse app has been downloaded more than 113 million times. Fans enjoy personalisation. They can set the name their idol uses to address them. They also access exclusive content. Yet, critics argue that monetising private communication encourages parasocial bonds.

Researchers warn that the rise of paid messaging platforms has reshaped fandom. The platforms have turned it into a more “convenient but passive” experience. This change disperses fan communities and replaces collective creativity with consumerism. Some subscribers even report feeling pressured to pay. They feel this way to be considered a “true fan.” They also scrutinize the frequency of messages as a measure of an artist’s authenticity.

Even traditional marketing tactics can encourage unhealthy spending. In Japan, AKB48’s annual “general election” allows fans to vote for their favourite member. Fans can vote only if they buy the group’s latest single. Each CD holds a voting code, so devoted supporters buy multiple copies to boost their chosen idol’s ranking. The Guardian reported that the 2012 election single sold a record 1.62 million copies in its first week and that one fan spent about US$6,700 to secure 2,700 votes. Such campaigns generate enormous revenue but reinforce the idea that affection is proven through consumption. Idol producers have tied handshake or meet‑and‑greet tickets to CD purchases. They have also tied them to merchandise. This further incentivises fans to buy dozens of similar products for a few seconds of contact.

Why Do Fans Cross the Line?

Toxic fan behavior stems from a combination of intense para-social relationships and an entertainment system that monetises proximity. Idol marketing encourages fans to see performers as friends or even romantic partners. Companies sell handshakes, signed merchandise and exclusive events, fueling the illusion of intimacy. For a small subset of fans, this illusion leads to entitlement. They believe they have the right to control or own the idol. When confronted with rejection or a perceived betrayal, they lash out.

Social media amplifies this dynamic. Sasaengs and anti‑fans can organise quickly through online forums, share personal information and coordinate harassment. The anonymity of the internet emboldens behaviour that would be unthinkable in person. Algorithms that reward outrage help such content spread.

Toward Safer Fandoms

Protecting artists requires collaboration among agencies, legislators, platforms and fans:

• Stronger enforcement – Laws like South Korea’s Stalking Punishment Act must be enforced consistently. Courts should impose meaningful penalties for stalking and information leaks, and police must act swiftly when performers report threats.
• Improved event security – After the AKB48 attack, Japanese idol groups added metal detectors and limited contact. Agencies should continue to reassess security at fan events. They must make sure there are barriers, bag checks, and trained staff ready to intervene.
• Responsible platforms – Social media companies and messaging apps must respond promptly to requests for user information. They must also remove posts that doxx idols. In 2022, Japan introduced a streamlined procedure. This allows victims to obtain a court order compelling platforms to reveal anonymous harassers. The process is reduced from six months to about three. A new law was passed in April 2025. It designates Google, LY Corporation (Line), Meta, TikTok, and X as “specified large‑scale telecommunications providers.” The law requires them to speed up the removal of defamatory content. Critics warn of potential overreach.
• Agency accountability – Entertainment companies must prioritise artist safety over profits. This includes providing bodyguards when necessary, paying for mental‑health support and taking legal action against stalkers. Agencies should also rethink promotional tactics. These tactics encourage obsessive behaviour. Examples include pay‑per‑minute phone calls or lotteries for one‑on‑one video chats.
• Fan education – Fandom communities can police themselves. Influential fan leaders and online moderators should emphasize boundaries and respect, report dangerous behaviour and discourage sharing of personal information. Many fans condemned the Enhypen dorm break‑in and urged Belift Lab to take stronger action.

Sources

BBC News — Coverage on Sulli and Goo Hara deaths
https://www.bbc.com

Reuters — Reporting on South Korea’s Stalking Punishment Act
https://www.reuters.com

The Korea Herald — Sasaeng and stalking law coverage
https://www.koreaherald.com

Yonhap News Agency — BTS flight safety statements
https://en.yna.co.kr

Soompi — ENHYPEN dorm intrusion statement
https://www.soompi.com

Journal of Fandom Studies — Parasocial relationship research
https://intellectdiscover.com/content/journals/jfs

Coming Up Next

Episode 6 will examine industry control and the power dynamics between companies and artists. We will explore how contracts, blacklists and cultural expectations give agencies immense control over performers’ professional lives. They also have control over personal lives. We will look at emerging efforts to reform this system.