What happens if there are two Smokestacks of Gnaak nearby each other?
See 'Example - Two Smokestacks of Gnaak' in the codex!
How do Smokestacks of Gnaak and Mirror Realm interact?
By the time Mirror Realm enters the realm, it's already a copy. Thus, it can copy a nearby site, and then promptly loses all abilities of that copied site (but still is the copy, without abilities). See 'Apply Ongoing Effects In Order' in the codex for nitty-gritty details.
How do Smokestacks of Gnaak and Rift Valley interact?
Rift Valley enters the realm using its , and only loses its once it's in the (which by then, it doesn't really matter).
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