Steffen "Rini" Udluft (born April 1969) is a German Doomer and speedrunner. He is most notable for maintaining the Doom and Doom II pacifist collections. From 1997 to 2001 he submitted 193 demos to Compet-n, first as a keyboard only player, then transitioning to keyboard and mouse. At Compet-n he recorded a large number of undone respawn demos and the first ever nm100s movie of The Shores of Hell.
Though demos in which the player ran to the exit without harming monsters had been recorded before, pacifist style became a separate category of speedrun play in May 1997 when Steffen Udluft emailed Frank Stajano, maintainer of the Doom Honorific Titles. Inspired by a growing trend of Compet-n speedrun submissions featuring 0% kills, Steffen suggested a DHT category where the player "Can do any level from scratch on Ultra-Violence without harming any monster". Within days a team of Compet-n and DHT players was assembled and began to assess the suitability of each Doom and Doom II level for pacifist speedrunning. During this period the accepted pacifist rules (such as disallowing intentional telefrags) were codified and 27 Doom and 22 Doom II levels were recorded pacifist style. These demos were bundled into collections which Steffen continued to maintain until 1999.