Activities
Helltide
A timed event that takes over part of the open world.
What it is
A Helltide floods a zone with demons for about an hour, with a five-minute gap before the next begins somewhere else. It opens once your account has finished the campaign.
Cinders and chests
Kills drop Aberrant Cinders. Spend them on Tortured Gift chests around the zone; each chest can be opened once per Helltide. Dying costs you half the cinders you are carrying.
Threat
Your threat rises as you kill, through three levels. At the third you are Hell-marked and ambushed, ending with a Hellborne. Clearing the ambush or dying resets threat.
The Blood Maiden
The Helltide boss is summoned at the Accursed Ritual with Baneful Hearts. The summon is announced to nearby players, so it is usually a group fight.
Chaos Rifts
Chaos Rifts also open inside Helltides. Opening one releases waves of much tougher enemies and a rift boss. They are a good source of seasonal reputation this season.
Season 15
With the Splinter of Terror, Helltide is one of your reputation activities, along with Infernal Hordes. Echoes of the Prime Evils can be announced during a Helltide and are worth killing for reputation.