For many years, Maciej “Groobo” Maselewski reigned as the unparalleled champion in Diablo speedrunning. His astonishing 3-minute, 12-second Sorcerer run, characterized by a mix of legal glitch exploits and what seemed like extraordinary luck in the game’s procedurally generated dungeons, appeared nearly impossible to surpass.

However, when a group of speedrunners began attempting to replicate Groobo’s success using external software and analytical tools, discrepancies in his gameplay started to surface. As the evidence of irregularities accumulated, this team proceeded to automate a search through billions of authentic Diablo dungeons, aiming to conclusively demonstrate that Groobo’s gameplay could not have occurred within any of them.

“Motivated by curiosity and a sense of resentment, we pushed ourselves to investigate further,” team member Staphen shared with Ars Technica regarding their inquiry. “Betrayal is another term that comes to mind,” added fellow team member AJenbo. “It was disheartening to discover that this achievement was seemingly obtained through illegitimate means… especially given all the accolades directed at the individual.”

Exploring the Nature of Luck

If you’re familiar with Diablo or the world of speedrunning, viewing Groobo’s run resembles watching a lottery win unfold. The dungeon features a layout of staircases that fortuitously connect close together, charting a swift, enemy-free route to deeper levels. On top of this, Groobo stumbled upon Naj’s Puzzler on level 9, a rare item essential for executing many late-game strategies that required teleportation.

“The proximity of so many levels with upper and lower sections right next to each other felt very strange,” observed Allan “DwangoAC” Cecil during a recent presentation attended by Ars Technica. “We aimed to find a method for replicating this setup.”

When Cecil and a group of tool-assisted speedrunners (TAS) fully embarked on this search last February, they used Groobo’s run as a reference point in their attempts to achieve an improved performance. While Groobo relied on his personal fortune to set up his run, the TAS team accessed tools and techniques from outside the game, enabling them to recreate Groobo’s performance—or something remarkably similar—consistently.