They may appear to be living but Guardians are actually mechanisms built by the Alimbics to guard sacred places and objects. The Guardian comes equipped with a huge variety of Alimbic weaponry including the Battlehammer, Volt Driver, Magmaul, and Judicator. They even have a version of Samus' Power Beam and Missile weapons. Each Guardian has a different weakness depending on its weapon. For example Guardians built with the Magmaul weapon are weak against the Judicator. The Guardians main weak point is the generator located inside the creatures’ cranium.
The generator inside the Guardians head area performs all the needs of the mechanism. It is built differently every time a Guardian is built with a new weapon. The Guardians that use the Battlehammer need generators that support the use and production of high-caliber weaponry. The ones built with Judicator are built to generate and charge Super-Cooled Plasma, super heated Plasma for Magmaul users and lastly a generator that picks up the electrical charge of the Planet its own. Built with long legs the Guardian can run up to 50 MPH.
The Alimbics created Guardians as defense mechanisms much like Alimbic Turrets. But the Guardian poses a striking similarity to an Alimbic. Nowhere near the technological advancements of the Slench or Crephtaphid the Guardians rely on sneak attacks and the "Strength in Numbers" philosophy. Guardians are usually placed near Artifacts or weaponry and when something is activated or taken it sends a signal to the Guardian which than attacks.