The Hunter β (ハンターβ,hantā bēta?) (development code: MA-121) was a prototype model for the Hunter line of Bio-Organic Weapons, designed as a derivative of the earlier α model. Unlike its predecessor, this prototype was developed by Umbrella Europe.
The Hunter β was developed by Umbrella Europe to improve upon Birkin's Hunter α work. Due to Umbrella's ability to clone B.O.W.s at a low cost, they were free to continue making further genetic modifications to the Hunter α, focusing on improving the Hunter's performance abilities. While its attack power was reduced in the process, its nervous system was improved, decreasing reaction time when being shot at.[excerpt 1]
In September 1998, Umbrella Europe was preparing final tests of the Hunter β before they could make the final decision on whether or not to mass-produce it. Taking advantage of the situation in Raccoon City later in the month, twenty of the Hunters were shipped to the United States and transported by truck into Raccoon City where the Umbrella Biohazard Countermeasure Service and their Monitors were to test and record the creatures' performance.