Once a regular Redding miner with a hobby focusing on magic tricks, Melchior's life took a turn for the worse when he was abducted by Enclave troops for slave labor in the Mariposa base. The event was witnessed by his son, Melchior Jr., who suddenly found himself orphaned.
Melchior and several other abductees were put to work removing tons of rock from the collapsed military base. Working without any protective gear, the slaves were exposed to FEV dispersed in the ruins and slowly began to mutate. The process was gradual, but noticeable. With the changes came the realization that the Enclave was going to execute them all once the work was complete.
That's where Melchior's talents came into play. He helped secrete away weapons and ammunition from their Enclave overseers, preparing an uprising. As the Enclave scientist retrieved a pure FEV sample and left together with the bulk of the Enclave's forces, the mutants attacked CaptainPickard's mop up crew. Sustaining heavy casualties, the troops fell back under the force of the onslaught and blew the entrance to the base, sealing Melchior and his mutants within.
Melchior is the boss character of Mariposa Military Base. The Chosen One should approach Melchior with caution as he will summon other monsters from the goo to attack. The monsters he summons are: four deathclaws, four floaters, four fire geckos and four mole rats. Melchior will summon monsters until there are four in total, and if any are killed he will summon more to maintain this number.
Surviving and killing all waves of his pets without killing Melchior results in humorous dialogue. "Uh oh, me outta furries to moottate."
↑Fallout 2 Official Strategies & Secrets p.205: "12. Melchior the Magnificent. Melchior is a sorcerer, of a sort. He throws rats into the pools of F.E.V. virus that fill the room, shown in Figure 10.13. The F.E.V. turns the rats into fierce monsters of all types, which, ravenously hungry after their metamorphosis, attack you on sight. Melchior has the last of the Military Base's holotapes on him, as well as a nifty Gauss Pistol. Your best bet to get Melchior is to fight his creatures in the narrow passageway before his room."