How does All Things Weaken interact with Heart of the Wildfire? When Wildfire places Presence, does it then destroy its own Presence?
No. All Things Weaken modifies how Presence destruction from Blight works, but doesn't change the source of the Blight, so Wildfire is still protected from Blight added due Spirit actions. This also applies to the portion which reads "...and 1 Presence in an adjacent land": if you choose Wildfire's Presence as the 1 Presence to destroy, it will survive if the Blight was added due to a Spirit Action.
While Volcano Looming High isn't protected from Blight added by Spirit Actions in general, it does have similar protection from Blight added by its Explosive Eruption Innate Power. In that one particular case, all of the above applies to Volcano Looming High as well. Tags: Actions, Blight, Blazing Presence (Heart of the Wildfire), All Things Weaken, 3 more...
The "Destructive Nature" special rule of Heart of the Wildfire protects its Presence from cascades caused by Spirit Actions.
Against the Habsburg Monarchy (Livestock Colony), if a single Ravage Action causes 8+ Damage to a land, then all of the Blight cascading from that Ravage also counts towards the Adversary's "Irreparable Damage" loss condition. (In solo play, this causes an immediate loss.)
Against the Tsardom of Russia Level 1+, Blight cascading from a Ravage destroys Beasts tokens due to "Hunters Bring Home Shell and Hide," possibly harvesting multiple Beasts tokens from a single Ravage Action.
Against the Kingdom of Scotland Level 5+, Blight cascading into a Coastal land from a Ravage triggers the extra Blight from "Runoff and Bilgewater" even if the Ravage Action was in an Inland land or on a different board. If Blight is added into multiple Coastal lands this way due to a single Ravage Action (e.g., if a Ravage in a Coastal land cascades into another Coastal land), only trigger "Runoff and Bilgewater" once. (Thus if a single Ravage Action adds Blight into Coastal lands on multiple boards, player choose which of those boards is "that board" for "Runoff and Bilgewater.")
However, cascading Blight against the Kingdom of Sweden Level 5+ doesn't activate the "Mining Rush" effect, since "Mining Rush" explicitly excludes cascades. Tags: Ravage, Blight, Victory and Defeat, Solo games, 6 more...