Use Eldritch Altars or defeat Witnessed Map Bosses with their respective Atlas Passive Keystones allocated the specified number of times.
Searing Exarch Altars with Wrath of the Cosmos Allocated. Wrath of the Cosmos: Eldritch Altars Influenced by The Searing Exarch have 50% chance to have an additional Upside. Eldritch Altars Influenced by The Searing Exarch which have an additional Upside have 100% increased Effect of Downsides.
Eater of Worlds Altars with Eldritch Gaze Allocated. Eldritch Gaze: Eldritch Altars Influenced by The Eater of Worlds have an additional Downside, Eldritch Altars Influenced by The Eater of Worlds have 50% increased Effect of Upsides.
Witnessed Map Bosses with Destructive Play Allocated. Destructive Play: The Maven casts Up the Stakes, summoning 1 to 3 additional Bosses when Witnessing Map Bosses. Modifiers to the Final Map Boss in each Map also apply to these summoned Bosses.