When Rek'sai's Legend ability allows you to play a card revealed from the top of your deck, does this bypass normal timing restrictions, and do you pay the cost?

Ruling: Any instruction that tells you to "play" something allows you to play that card regardless of normal timing restrictions. You do pay the cost for the card when playing it via Rek'sai's ability.

Sequence:

• Exhaust Rek'sai when you conquer
• Reveal the top 2 cards of your Main deck
• You may play one (paying its cost)
• The card goes to pending
• Finish resolving Rek'sai's ability
• Recycle the rest

Nuances:

• This differs from effects like Dazzling Aurora which explicitly state you do not pay the cost