Passive Souls, as their name suggests, grant base stats or an ability that applies as part of a large action or automatically throughout the game. Each player can carry a total of 4 passive souls but there are two passive soul slots that take priority in placing the soul in your inventory. On the other hand, each player can only carry two active souls which have their own assigned item slots. (Num. 4, Num. 5)

List of passive souls (notation of x / xx / xxx refers to having rank1 / rank2 / rank3 of the soul):

Basic Souls Description
Dire Soul [Dire Soul] While life is below 600, gain Regeneration which will restore 500 life over 10s. This has a 45/30/15s cooldown.
Wise Soul [Wise Soul] While mystic guard is off cooldown, your abilities will cooldown 6/9/12% quicker.
Frightened Soul [Frightened Soul] If you take or prevent 150 or more damage in a single attack, you will gain a significant movement increase and reduce the potency of slows by 80% for 5s. This effect has a 45/30/15s cooldown.
Boss Souls
Ai's Fluidity [Ai's Fluidity] Movement speed is increased significantly for 2.5/3.75/5 seconds after using Mystic Guard. Has a 16s cooldown.
Arcane Soul [Arcane Soul] If you haven't taken damage for 5 seconds, your abilities will cooldown 8/12/16% quicker and mana will regenerate at 0.5/1/1.5 mana per second.
Brave Soul [Brave Soul] Life is increased by 500/750/1000, but movement speed is slowed by 4/6/8%.
Celestial Soul [Celestial Soul] Basic attacks have a 20% chance to restore 35 mana and call down a star, dealing 110/165/220 damage to nearby enemies. Has a 20s cooldown.
Fairy Soul [Fairy Soul] Basic attacks have a 25/37.5/50% chance to summon a Fairy that will heal you or an ally for 225 life instantly. Prefers low life targets.
Gaia's Grace [Gaia's Grace] The potency of slows is reduced on you by 50/70/90% and damage you take is reduced by 5/7.5/10%.
Gaven's Fortitude [Gaven's Fortitude] After using mystic guard, damage you take is reduced by 20/30/40% for 6 seconds.
Guardian Soul [Guardian Soul] If damage taken in a single attack is 250 or higher, automatically activate mystic guard preventing the damage and all further damage for 1 second. This will not trigger mystic guard's cooldown. Has a 65/55/45s cooldown.
Lord's Madness [Lord's Madness] Every 15/10/5 seconds a random effect will occur. This can be positive or negative.
Molten Soul [Molten Soul] Enemies that deal damage to you from any distance will take 70 damage. This effect has a 6/5/4 second cooldown. On death you will explode, dealing 500/750/1000 damage in a large area. The death effect can only occur twice per boss fight.
Necromancer's Soul [Necromancer's Soul] Units killed by you have a 30/45/60% chance to come to life as skeletons that will attack nearby enemies. Skeletons prefer low health targets and have a ranged attack. They live for 3 seconds.
Prophet's Foresight [Prophet's Foresight] While mystic guard is active, 40/60/80% of the damage prevented is converted to life.
Radiant Soul [Radiant Soul] Restores 20/30/40 life per second to yourself and allies around you. On death, explode with light, restoring 1000/1250/1500 life to all allies.
Reckless Soul [Reckless Soul] Your damage output is increased by 14/21/28%, but at the cost of 250/375/500 max life.
Rogue's Soul [Rogue's Soul] Greatly lowers the likelihood that you will be targeted by boss abilities and attacks and increases attack speed by 12/18/24%. (At rank 3 this sets your AA swing timer to T/1.24, which is 1.21s for ranged and 1.61s for melee)
Varenel's Shadow [Varenel's Shadow] Your life is restored by 50/75/100% of the damage you deal and your damage output is increased by 6/9/12%.
Zephire's Instability [Zephire's Instability] Whenever you deal damage, you have a 20/30/40% chance to unleash a lightning strike on your target for 20 magic damage. This effect has no cooldown.

All souls updated for patch 4.8Edit
Community content is available under CC-BY-SA unless otherwise noted.