Mastercraft armor and weapons are exceedingly powerful sets of items that typically confer come extra benefits on the bearer if they are wearing/wielding the full set and have the set's associated pet out (if there is an associated pet to the set). For example, wearing the dragon knight's hide and the dragon knight's crest, and wielding the dragon knight's scales and the dragon knight's fangs grants access to the fire breath ability and the half-dragon transformation skill; wearing/ wielding those items allow the dragon knight's familiar to inflict bleeding damage on your foes.