User blog comment:Kogath/Monster Hunter Generations Discussion/@comment-26995086-20160819122556/@comment-5569775-20160819215449

In general, I just use the Fatalis armor as the lore explanation. The Armor usually talks about how the armor tries to take over you and corrupt you, devouring your soul via the remnants of the great dragon. It's possible that all armor still retains some of the power or traits associated with the monster it's made from, and that power influences the hunter, directly increasing said hunter's capabilities.

But that only works for armor made from monsters/insects.