In March 1996, Blizzard Entertainment acquired Condor, which was renamed into Blizzard North. On December 31, 1996, Blizzard released their first game of the company's successful series, Diablo. His work in Diablo was so well received that Uelmen was loaned to Blizzard's StarCraft team (but stayed in Redwood City), where he did sound design; that game was released two years after Diablo, in 1998.
On June 29, 2000, Blizzard launched the second game of the Diablo series, Diablo II. In 2001, Uelmen, who composed the Diablo II Soundtrack, and cinematic soundtrack composers Jason Hayes, Glenn Stafford and Andrea Pessino won the International Game Developers Association award for Excellence in Audio for their work on Diablo II. Continuing his work in the Diablo series, on June 29, 2001, Blizzard launched what would be believed to be the last game of the series, the expansion pack . In an interview with Gamasutra, Uelmen was asked about his time at Blizzard between 2001 and 2005. When asked whether he had worked on the earlier version of Diablo III prior to the shutdown of Blizzard North, he responded, "I guess at this point I can say, yes, more or less. Blizzard has always had a number of projects, though, that may or may not see the light of day. Some of those have been talked about, but there definitely was more than one thing going on development-wise at the time."
