For a variety of reasons, powerful casters will create constructs (also called golems) to serve them—often long after their own death. Constructs have no metabolism, are immune to the Alteration, Command, Necromancy, and Earth effect groups, and are always immune to the Poison qualifier. Some constructs require special weapons to affect; for example, Magic weapons will often inflict full damage where normal weapons might not.
Often, constructs will take damage from Shatter effects, and may not be able to defend normally against these. If you want to harm a construct with a Shatter, you should target their body (e.g. “Weapon Strike Shatter Body!”). Constructs might be healed by rituals or specific elements (such as Flame or Lightning). Often, they are virtually mindless, following the simple commands of their creator until otherwise ordered.