The killing of a Taiwanese teenager in a brutal knife attack over a dispute involving the Blade&Sword Online game has raised concerns over computerised depictions of violence.

"[The assailant] didn't know the difference between reality and fantasy," lamented the Apple Daily, which splashed a graphic illustration of the assault, which took place in an internet cafe, across its front page on Tuesday.

The local TVBS news station suggested the violence of the game played a role in the attack.

"In a bottom corner of the screen, there's a sign that pops up and tells players to 'kill until your eyes are red’,” a TVBS commentator said. In local culture, red eyes are associated with extreme anger, bordering on insanity.

Blade&Sword’s maker, Pixel Studios of Beijing, was not immediately available to comment on the incident on Wednesday.

The dispute occurred after the 19-year-old killed in the attack, Lee Hon-hui, used his character in Blade&Sword Online to slay that of an opposing player. Angry about being knocked out of the game, the alleged assailant left the internet cafe and headed straight for a hardware store to buy a long, machete-like knife, according to TVBS. He then allegedly returned and attacked Lee.