Zaero: Episode 1 is a three-level PWAD for Doom II, released in June 2005 by Steven Searle. Built for the ZDoom source port, Zaero is heavily inspired by Quake II and features a similar aesthetic, with the gameplay enhancements being reinforced by the addition of several custom enemies through DECORATE. Planned to be the first entry with more maps to come, no sequel ever materialized.