This is a spoiler for Ashiok, Nightmare Muse, a planeswalker in the upcoming expansion. Their ult reads:
You may cast up to three face-up cards your opponents own from exile without paying their mana costs.
Certainly, this applies to adventure cards the opponent has exiled by playing them as adventures.
The question is, may the controller of Ashiok cast those adventure cards as adventures, or does the restriction to the non-adventure part from exile apply to all players?
The rules on adventure cards say:
715.3d Instead of putting a spell that was cast as an Adventure into its owner’s graveyard as it resolves, its controller exiles it. For as long as that card remains exiled, that player may cast it. It can’t be cast as an Adventure this way, although other effects that allow a player to cast it may allow a player to cast it as an Adventure.
The first half of the third sentence says
It can’t be cast as an Adventure this way
Does "this way" refer to "anyone casting it from exile", or does it refer to "that player [the player who put it into exile by casting as adventure] casting it from exile"? I am not sure because the second half of the sentence says
other effects that allow a player to cast it may allow a player to cast it as an Adventure.
which refers to "a player" rather than "that player".
So does that "other effect" specifically have to allow casting the card as an adventure, i.e. Ashiok would only allow the non-adventure part to be cast?