Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island)

When the Mentor Aspect is the target of Unlock the Gates of Deepest Power, what happens?
Shifting Memory of Ages draws two Major Powers, gains them both, and forgets nothing. If they meet the threshold requirements, they can play one of the new Power Cards – since the identity of "the Major Power" is ambiguous, Shifting Memory of Ages chooses which one is being referred to.
It doesn't matter who played the Power, just that Shifting Memory of Ages with the Mentor Aspect is the target.
Tags: Gaining Power Cards, Unlock the Gates of Deepest Power, Mentor Aspect (Shifting Memory of Ages), Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island), 0 more...

If you gain presence during the turn (after Growth) and uncover the "any" or another element, can you then use it for other powers?
Yes, you can start using elements as soon as you gain them. (p. 14) Similarly, if you are able to play a card mid-turn, you get the effects of its Elements immediately.
(And if some effect were to cover an Element by returning Presence to your track, or destroy a Power card in play, you'd immediately lose access to the elements.)
(Discussion elsewhere) Tags: "Any" element, Elements, Adding Presence, Indomitable Claim, 13 more...

When an effect lets you play a card, does that count against your allowed number of card plays?
No. The number of card plays on your Presence track only affects how many cards you can play as part of the "Play and Pay For Power Cards" action in the Spirit Phase. Cards played any other way (usually in the Fast Phase when instructed to do so by a Power) are in addition to those limits.
(Discussion elsewhere) Tags: Playing Power Cards, Spur on with Words of Fire, Unlock the Gates of Deepest Power, Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island), 14 more...

Does an "or" line on a power divide the entire card?
No. The "or" line only applies to the clauses immediately above and below the line, without extra whitespace.
For example, if you use Crops Wither and Fade, you always gain 2 fear and then you may choose whether you are replacing a City or a Town. On the other hand, on Tormenting Rotflies, you either choose everything above the "or" or everything below it.
To be explicit, the following cards have clauses that are not part of the "or" choice (separated by whitespace): Crops Wither and Fade; Growth Through Sacrifice; Sacrosanct Wilderness; Gift of the Primordial Deeps; Gift of Flowing Power; Call to Guard; Vanish Softly Away, Forgotten by All; Thickets Erupt with Every Touch of Breeze
(Discussion elsewhere) Tags: Crops Wither and Fade (Shadows Flicker Like Flame), Growth Through Sacrifice, Sacrosanct Wilderness (Keeper of the Forbidden Wilds), Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island), 15 more...

When playing Ward the Shores, if you play a Power Card not during the Spirit Phase, can you play it face-down to add a warding pattern?
Yes, subject to the "once per turn" limit.
(Discussion elsewhere) Tags: Playing Power Cards, Ward the Shores, Spur on with Words of Fire, Gift of the Primordial Deeps (Serpent Slumbering Beneath the Island), 4 more...
In Destiny Unfolds, if you only have Major Powers in your Destiny, can you gain Minor Powers normally from the deck? (Or vice versa)
Generally no. Rather than choosing a deck to gain from, you choose a single Power in your Destiny to gain. If your Destiny only has Major Powers, you must gain a Major Power.
However, if the source of the Power Card forces you to gain a Minor Power (e.g., "Gift of Power") and you have none in your Destiny, gain one normally from the Minor Power Deck (and similarly for an effect that specifically gains Major Powers).
Tags: Gaining Power Cards, Call on Midnight's Dreams (Bringer of Dreams and Nightmares), Boon of Ancient Memories (Shifting Memory of Ages), Unlock the Gates of Deepest Power, 12 more...