A creature is one of the basic entities in the game world of Guild Wars. It is used to represent almost all living and animated beings, and even a few inanimate things, such as Xunlai Chests. Although player characters are creatures, this article focuses on non-player characters.
There is no classification system officially given as canon that completely covers all creatures. Various game mechanics, lore, and official statements have been used to piece together as comprehensive a picture as possible. There are several classification systems, which overlap each other:
- Creature type is a classification that corresponds to the physical and biological form of creatures. Examples include Charr, Dryders, and Shiro'ken.
- Affiliation is general term for an organized group with something in common that fights together for a cause. Examples include the Jade Brotherhood, the White Mantle, and the Mursaat. Non-sentient creatures generally belong to regional wildlife groupings.
- Species is the lore classification of creatures. Examples include humans, asura, and skale.
 Variable traits
- Some creatures have skills which give them extra abilities, such as Stun Immunity, which prevents knockdown.
- Most bosses have Natural Resistance.
- Foes in Hard mode are given several benefits, see the page for details.
- Creatures may have altered armor against damage types. Examples:
- Many plant creatures are vulnerable to fire damage and slashing damage.
- Most Skeletons have -20 armor against blunt damage and +20 armor against piercing damage.
- Many ghosts have increased armor against physical damage.
- Many fire elementals are strong against fire damage and weak against cold damage.
It should be noted that although these traits may be strongly associated with a particular type or affiliation, they are not rigidly tied to creature classification. One example is the trait of taking double damage from holy damage. Despite being widely prevalent among the undead, Undead Sensitivity to Light is determined independently for each creature. Contrary to the implications of in-game descriptions it may not strictly match any other identifier for the undead including general lore, the deathbane mod, or the Undead Hunt bounty.
All creatures in explorable areas are also grouped into parties. Although most creatures hostile to player characters work together, there are some groups that are hostile to each other. This can be easily seen in many areas of The Jade Sea where roving groups of Outcasts will attack anything that they come across.
 Armor ratings
Creatures other than player characters have their basic armor rating decided by their level and profession. This may be tweaked in one way or another, such as Wurms having very high armor, or changed versus certain types of damage, such as lower armor against fire damage. Warriors and paragons may or may not have shields when wielding a one-handed weapon.
The basic formula is: 3 * creature level + armor bonus
For example, a level 24 Margonite Bowmaster would have 82 base armor rating (72 from being level 24 and 10 from being a ranger) and 112 armor against elemental damage.
In Hard mode, foes that are below level 20 in Normal mode generally have the armor that they would have if they were level 20. Foes that are above level 20 in Normal mode have the same armor in Hard mode as in Normal mode.
A creature's energy is based on their profession and is usually as follows: