Chang Wen  was a 27-year-old Taiwanese man born in 1998. Details about his early life remain limited, though it is known that he previously served in the Republic of China Armed Forces. He was discharged after being caught driving under the influence of alcohol. According to investigators, Chang had been estranged from his family for over two years and had not maintained contact during that time.

Chang had reportedly been unemployed for one to two years prior to the attacks and was under investigation by authorities for failing to report for reserve military training, a breach of Taiwan's military service regulations. As a result, the Taoyuan Prosecutors Office had placed him on a wanted list. His cloud backup records indicated that he had researched incidents of "random killings," including the 2014 Taipei Metro stabbing attack.

In early 2024, Chang began actively planning his assault. He began purchasing smoke grenades, gas canisters, respirators, tactical gear, and knives. He rented an apartment in Taipei’s Zhongzheng District in January 2025 and conducted location scouting around Taipei Main Station and Zhongshan Station. By December, authorities believe he had finalized his plan to execute a multi-stage public attack.

On 19 December 2025, Chang Wen initiated a coordinated series of attacks across multiple locations in Taipei, Taiwan. Prior to the physical assaults, he committed two acts of arson, setting parked vehicles ablaze on roads in Zhongshan District. He also set fire to his own apartment building. These initial attacks were later revealed to be distractions or preludes to his main assault.

At approximately 17:24, Chang was seen near exits M7 and M8 of Taipei Main Station wearing black body armor and a gas mask. He removed a smoke grenade from a suitcase and activated it, filling the immediate area with thick smoke. During the confusion, 57-year-old Yu Chia-Chang attempted to intervene but was stabbed with a long knife and later died at National Taiwan University Hospital.

Following the first attack, Chang fled to a nearby hotel near Zhongshan Station, where he changed clothes and retrieved additional weapons. Around 18:00, he returned to the public with more smoke grenades, this time deploying them outside the entrance to the Eslite Spectrum shopping center. In the midst of the chaos, he began indiscriminately slashing civilians in the crowd. Multiple surveillance and bystander videos captured him casually tossing grenades into crowds on sidewalks and within underground areas.

As he fled the scene and ran into the Eslite building, Chang eventually reached the rooftop. In the final moments of the incident, he fell from the roof of the Nanxi branch of Eslite Bookstore and was later pronounced dead at Cathay General Hospital after failed resuscitation efforts.

Three people were killed in the attacks: Yu Chia-Chang and two unnamed 37-year-old male victims. Eleven others were injured, with at least two in critical condition the following day. Reports indicated that some victims suffered knife wounds to the neck, while others were treated for minor injuries. Six of the injured individuals sought medical treatment on their own.

On 20 December, Taiwan’s CDC confirmed that one of the injured victims was HIV-positive, though with an undetectable viral load. Because his blood was splattered at the scene and on a shared weapon, authorities initiated a public health response. This included post-exposure counseling and publicly funded antiviral medication programs to prevent potential transmission to other victims.

Heroic efforts by bystanders did not go unnoticed. Taipei Mayor Chiang Wan-an commended Yu’s actions in attempting to confront the attacker. The city awarded NT$6 million in condolence payments to Yu’s family and confirmed that Taipei Metro Corporation would provide NT$5 million more and install a memorial plaque. A separate victim, a 37-year-old bank employee, also received support from Mega International Commercial Bank, which covered funeral expenses and issued bereavement benefits.

One other 37-year-old victim, stabbed on a public road rather than within Eslite or Taipei Metro premises, faced difficulty qualifying for standard insurance payouts. In response, the city offered support via victim aid associations, social programs, and public donations.

Following the incident, a task force from the Taipei District Prosecutors Office directed evidence collection at multiple crime scenes, including Chang’s hotel, apartment, and public transit locations. Investigators recovered numerous weapons and incendiary materials, including 17 smoke grenades, 15 molotov cocktails, tactical vests, and knives. A plan for the attack was also retrieved from a cloud drive. Authorities confirmed that Chang acted alone and had deliberately imitated aspects of the 2014 Taipei Metro attack.

Police found Chang’s cloud-stored attack blueprint and discovered encrypted data on his ROG gaming laptop’s solid-state drive, which had been partially burned. The drive used BitLocker encryption and could not be cracked by authorities, despite assistance from ASUS and Microsoft. Attempts to access Apple devices linked to the attacker were also unsuccessful, as the devices auto-disconnected when connected to forensic software like Cellebrite and GrayKey.

In the days following the attacks, Taiwan increased security measures across major transit and public areas. The Zhongshan-area market was closed for three days, and citywide police presence was doubled in anticipation of the Taipei Marathon on 21 December. Flowers and condolences were placed at the MRT station exits where the stabbings occurred. Additionally, the National Police Agency began investigating a wave of threatening online posts referencing the incident. Within days, several individuals were arrested in connection with threats to carry out similar attacks.