This profession guide is accurate as of BWE2.
The guardian is a devoted fighter who calls upon powerful virtues to smite enemies and protect allies. As dangerous with a staff as he is with a mighty two-handed hammer, a true guardian is a master tactician who knows when to sacrifice his own defenses to empower his allies to achieve victory.
-Official Guild Wars 2 Website
The guardian, as the name suggests, is a highly defensive class. Even though they wear heavy armor, guardians have very little health compared to other professions. They make up for this with a myriad of powerful defensive abilities. A lot of their abilities simultaneously have both offensive and defensive uses, many of which involve burning opponents. They have a unique mechanic that takes the form of virtues: passive bonuses (occasional burning attacks, aegis every 40 seconds, healing) that can be sacrificed for a short time to give a similar bonus to nearby allies. The guardian also produces many symbols on the ground: AoE abilities that hurt enemies and help allies.
Greatsword – The guardian’s greatsword is the definition of offense for guardian. Not only does it offer burning, might, and retaliation at close range (like Symbol of Wrath) it even has two powerful gap closers (like Binding Blade).
Hammer – Where the greatsword gives offensive power, the guardian gives defensive power, though it can be used as both. While it has no gap closers, it has great ability to keep opponents in melee range — or out (such as Ring of Warding and Zealot’s Embrace).
Staff – The staff is a mid-ranged option for the guardian that is largely defensive and full of utility in place of straight offense or defense like the other two-handed weapons (e.g., Line of Warding or Martyr). Because of this, the staff is a better secondary weapon than primary weapon in a build.
Mace (MH) – The mace is a highly defensive one-handed weapon that provides options for healing, protection, blocking, and even condition removal by itself using a combo between Symbol of Faith and Protector’s Strike.
Scepter – The scepter is the long-range option for the guardian, though its auto-attack is slow. It’s also offensively oriented with abilities like Chains of Light.
Sword (MH) – The sword, much like its two-handed counterpart, is an offensive weapon complete with a very useful gap closer in the form of Flashing Blade.
Focus – The focus is a strong off-hand with both skills being a part of the offensive-defensive duality of the class (for example, Ray of Judgement).
Shield – As expected, the shield is a fully-defensive off-hand weapon with a considerable amount of power in its skills like Shield of Absorption.
Torch – The torch is a particularly fun off-hand weapon with interesting fire-based abilities. It’s mostly offensive in nature, including the ability to set yourself on fire and throw your Zealot’s Flame at enemies!
Spear – The spear forms the guardian’s offensive abilities underwater, fighting at a medium and short range with abilities like Zealot’s Flurry. As with any close-range weapon, it has at least some ability (Brilliance) to keep yourself alive at such a short range.
Trident – The trident is the opposite of the spear: a long-ranged defensive weapon with terrific ability to remove conditions from allies with Purify and keep foes away from you by sinking them with Weight of Justice.
The guardian’s slot skills also do a good job of keeping with the mostly defensive skills and many duality skills. The healing skills unfortunately have long cooldowns, with the shortest being the Signet of Resolve, which offers the most amount of healing over a long period of time. Healing Breeze is good when in working in close-together groups, and Shelter leaves the most to be desired, though the block makes it powerful if used well.
Consecration – All of the consecration skills are AoE abilities of a defensive nature. The most powerful non-elite defensive slot skills the guardian has are consecration skills. While initially targeted at your location (excepting Wall of Reflection), traits can make them ground-targeted.
Meditation – Meditations are all slot skills with an associated cast time that can be removed via traits. Two of them teleport you to either an enemy or ally, while the other two remove conditions. Meditations are fairly balanced between offense and defense.
Shout – All of the shouts are defensive, instant, multi-target buff skills. While not overly powerful, they do have relatively medium-length cooldowns (excepting “Retreat!”)
Signet – As with all signets, each skill as a passive ability that is put on recharge when its activated component is used. It is here that the guardian’s instant-revive ability, Signet of Mercy, lies. Signets are all either offensive or defensive without duality functions, with two of each.
Spirit Weapon – The spirit weapon skills summon a spirit weapon (hence the name) that follows the guardian around for a time and contributes to fights in its specialized role. Each of the weapons also has an ability that can be activated at the cost of destroying the weapon.
Elite – The Renewed Focus elite has an incredibly long recharge for a tiny duration, making it generally the least impactful elite the guardian has. The other two, Tome of Courage and Tome of Wrath, hold the guardian stationary while granting access to immensely powerful defensive and offensive spells, respectively.
The guardian’s five trait lines are named after personality virtues. The fifth, Virtues, contains Willpower - the guardian’s unique attribute that reduces virtue recharge.
Zeal (Pow/Exp) – The minor traits all involve symbols and their augmentation. The major traits give bonuses to spirit weapons, greatswords, scepter damage, and burning. The final traits in the line are Wrathful Spirits and Zealous Blade.
Radiance (Pre/Mal) – The minor traits boost Virtue of Justice (the burning virtue) and damage to conditioned foes. The major traits augment blindness, burning, signets, sword damage, spear damage, and torch skilll recharges. The final traits in the line are Perfect Inscriptions and Right Handed Strength.
Valor (Tou/Pro) – The minor traits give automatic Aegis at low health, recharge Virtue of Courage (aegis virtue), and give might on blocking. The major traits have buffs to meditation skills, shield skill recharges, toughness increases, mace damage, periodic condition removal, and more healing. The final traits are Altruistic Healing and Monk’s Focus.
Honor (Vit/Com) – The minor traits give vigor on criticals, healing on dodges, and increased damage at low health. The major traits give significant bonuses to honor and symbols, bonuses to reviving, bonuses to shout recharges, and two-handed recharges. The final traits are Battle Presence and Pure of Voice.
Virtues (Con/Wil) – The minor traits augment add boons to your virtues and give bonus damage for boons. The major traits augment your virtues, lengthen retaliations, buff consecrations, and extend elite skill durations. The final traits are Extended Consecrations and Judgemental.
The guardian is a fairly simple class with significantly less to keep track of than many other classes. The general underpowered nature of the virtues’ activated components (in their natural form) give less to focus on, making the guardian a good class for beginners. While being in melee is more hazardous than ranged, the guardian’s superb defenses make it an especially good place for beginning melee players, in both PvE and PvP.