Centuries ago The Yirbeks governed a small empire in the Skrull galaxy. During an intergalactic war, these humanoid reptilians drove The Kallusians out of their home planet. Many years later, The Yirbeks discovered The Kallusians hiding on Earth and the two races resumed their bitter feud. Although the outcome of that battle is unknown, The Yirbeks where eventually defeated by The Skrulls. They have served The Skrull Empire ever since.
The Kallusians were created by writers Stan Lee, Paul Laiken and Larry Lieber and artists Jack Kirby and Don Heck in 1965.