<P> J. Neilson, a knife and sword expert, holds the rank of Master Smith within the American Bladesmith Society . He has over 20 years' experience in making knives and edged weapons . He examines the weapons' technical qualities and tests their durability . In Season 3, Neilson took a leave of absence in order to have surgery on his hand; Jason Knight, another ABS Master Smith, filled his seat on the judges' panel during that time . Neilson appeared alongside Knight for the Season 4 premiere, then resumed his seat in the eighth episode . Starting with the 21st episode of the fourth season, he was replaced by two - time Forged in Fire champion Ben Abbott . </P> <P> David Baker, a Hollywood prop maker who has appeared on the Spike series Deadliest Warrior, is an authority on weapons history and an expert on replicating period - accurate weapons for both museums and films . He judges the weapons' historical accuracy and aesthetic beauty . </P> <P> Doug Marcaida, an edged - weapons specialist, is a U.S. military contractor, martial arts instructor and knife designer for FOX Knives Italy . Specializing in the Southeast Asian fighting style of Kali, he has taught classes in weapon awareness and use for military, law enforcement, and security organizations . Marcaida evaluates the smiths' weapons to determine their effectiveness in combat . When he cannot test the smiths' weapons himself due to injury, he has a co-worker or family member perform this task in his place . </P> <P> Tim Healy and Steve Ascher are executive producers for History . Jodi Flynn, Brent Montgomery, David George, Shawn Witt and Simon Thomas are executive producers for Outpost Entertainment . Healy observed the demonstration, and later the filming, from the sidelines . Healy says that the inspiration for Forged in Fire came from his and other developers' love of food competition shows such as Chopped and Iron Chef . However, in order to appeal to the History channel's audience, they decided to have the competition focus on historical weaponry . </P>

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