Board Thread:Suggestions forum/@comment-31907131-20170417102331/@comment-28794147-20170419034636

Recneps wrote: Resistant to fire means incorruptible? Also, they were incorruptible, as they were already corrupt. Their greed took a higher priority than almost anything else in many of their stories.
 * massive facepalm

Tolkien was never symbolic when he wrote. He literally meant they forged great armor that made them withstand dragon's flames.