The text has since been updated to confirm that the effects also do not function inside battlegrounds or arenas.
Obtained by completing Prey hunts and Delves in Season 2, Corrosive Soul allow players to add new enhancements to bracers and belts, marking them with the Corrosive tag, and giving players a little bit more power in the open world. They are explicitly not active inside dungeons, raids, battlegrounds, or arenas, serving instead to help players overcome newfound dangers within the Coiled Isle, as well as Delves, Ritual Sites, and other "world-tier" content.
The Corrosive Codex allows players to preview all of these powers in-game. Extras can be purchased from Naleidea Rivergleam.
Here is a list of all the Corrosive powers!
Ophidian Maw - Damaging an enemy has a chance to call a giant snake that erupts from below, gnashing at the target's location and dealing Nature damage split between nearby enemies.
Any Poisoned non-boss creature damaged below 20% health is executed.
Viperine Grasp - Your harmful spells and abilities have a chance to pull up to 2 nearby enemies to your current target's location, dealing Nature damage to affected targets.
Up to 3 nearby Poisoned enemies are also pulled in.
Mephitic Cloud - Chance during combat to apply Mephitic Cloud to nearby party members and enemies for 10 sec.
Afflicted allies' spells and abilities Poison their target, dealing Nature damage over 5 sec, while afflicted enemies' spells and abilities additionally heal their target.
Gorgoneion Gaze - Upon dropping below 50% health, petrify all enemies within 10 yards for 10 sec. Petrified targets are stunned and invulnerable.
When they break free, enemies are Poisoned, taking Nature damage every 1 sec and slowed by 50% for 5 sec.
Lithic Plumage - Taking damage has a chance to fortify you, reducing incoming damage by 75% up to a cap.
The damage cap is increased for each nearby Poisoned enemy.
Ouroboric Cycle - Chance during combat to begin an Ouroboric Cycle, increasing all Tertiaries for 5 sec, then all Secondaries for 5 sec, then your Primary Stat for 5 sec.
In this state, slaying an enemy causes 1 additional Cycle to occur after the last.
While you are Poisoned, each Cycle's duration is extended by 1 sec.
Insidious Venom - Chance during combat to Poison yourself, lowering all of your Secondary and Tertiary Statistics while greatly increasing your Primary Stat for 12 sec.
Virulent Mucus - Upon entering combat, veil yourself in 5 layers of Virulent Mucus, each stack negating an instance of incoming damage that would exceed 5% of your maximum health.
Dealing damage to a Poisoned enemy has a very low chance to grant you 1 additional layer of Mucus.
Accursed Poison - Chance during combat to inflict Accursed Poison on the strongest enemy, dealing Nature damage every 1 sec for 1 min.
The next time the afflicted target would cast an interruptible spell or ability, the Accursed Poison triggers, interrupting it immediately before removing itself.
Plague of Corrosion - Chance during combat to apply a stacking Poison to all nearby enemies, dealing Nature damage every 2 sec for 1 min.
On death, the Poison and its remaining duration are transferred to a new target.
Miasma Geyser - Chance during combat to stir up a Miasma Geyser under a nearby unit that erupts after 10 sec, dealing Nature damage split between enemy units while also healing all allies inside.
Poisoned units take increased damage and healing.
Ula'tek's Gift - Your harmful spells and abilities have a chance to afflict your target with 5 stacks of Ula'Tek's Gift, dealing Nature damage per application every 5 sec for 1 min.
While you are Poisoned, apply 5 additional stacks.
Upon applying 20 stacks to a target, the Gift Corrodes, dealing the remainder of its damage immediately before removing itself.
Most of the enhancements share a venomous theme, with increased effects when the user or target are poisoned. Combined with the re-usable nature of the Corrosive Soul means that players can effectively farm for synergistic combinations or whatever happens to be the strongest effect. That the developers have chosen to use poison, rather than a unique term, would suggest that other player and enemy applied debuffs will also trigger these synergies, though that has yet to be confirmed.
The Insidious Venom proc more than doubles strength at 290 item level, but really does reduce all other stats, even tertiary leech, speed, and avoidance!
Not all of them are pure damage or statistical effects either. Virulent Mucus and Accursed Poison in particular stand out as very interesting effects, though an expected one proc per minute keeps them from being particularly reliable.
