The monsters in this dungeon are randomly picked from the different tiers of slayer areas, with some special modifiers applied to them, as described in the mechanics below.
Event Mechanics
Starting the event will make the player unable to fight any monsters outside of the event. Any time while not actively in combat with event enemies, the event will be paused and the play may train non-combat skills. The event's progress is saved while paused. The only way to stop the event is by dying or using the Stop Event button.
This is a safe death for hardcore characters: Hardcore characters that die receive the normal death penalty of losing an equipped item, but the save file will not be deleted.
The event takes place over 5 rounds of combat. At the beginning of each round, the player will select a random modifier that applies to all monsters for the rest of the event. During each round, the player must defeat all monsters in four Slayer Areas - Shrouded Badlands, Perilous Peaks, Dark Waters, and Unhallowed Wasteland. Since all combat takes place in Slayer Areas, the player must have access to that area granted by the Slayer Skillcape or the specific item required by each area. Unequipping these items after entering combat will cause the player to be unable to deal damage to the enemy until the item is re-equipped. Similarly, all Slayer Area Effects are always in place while in that area, and must be dealt with accordingly.
Entering a Slayer Area will pit the player against a gauntlet of 5-8 monsters chosen randomly from the monsters in that area. The final monster will be empowered with the "Mist Boss" passive ability that grants the enemy +20% Maximum Hitpoints, +20% Damage Reduction, -20% Attack Interval, +20% Accuracy Rating, and +20% Global Evasion.
Upon completion of the fourth Slayer Area, the event will pause and the player will be presented with the true boss of the round, Bane. Bane's combat style is randomly selected each time he appears, and similar to Into the Mist, the player must use the same combat style in order to defeat him. If the player is unhappy with the selected combat style, fleeing from combat and redoing the last Slayer Area will cause his style to be randomly selected again. Defeating Bane will end the round and reward the player with the next reward from the list below.
The item rewards for completing Impending Darkness Event are:
Completing Impending Darkness Event adds Impending Darkness, a lore book, to the bank.
Impending Darkness Event always grants these item rewards in this order. The lore book will be added to the player's bank even if they do not have space, if no bank slots are available, it will overflow the bank. This is NOT true for the shields and ring. Multiple copies of each item can be obtained by completing the Event multiple times.
At the end of the 5th round, the final boss will be Bane, Instrument of Fear. This final boss is a more powerful version of the others, has more hitpoints, a powerful additional special attack, and has the cumulative effect of all negative modifiers chosen over the course of the event. Defeat him to claim victory over the impending darkness!