Can I activate Le Blanc Deceiver's ability when I hold a battlefield but have no cards in hand to discard?

Ruling: No, you cannot activate Deceiver's ability if you have no cards in your hand. The discard is a cost (appearing before "to" in the ability text), not part of the effect's resolution, so you must have at least one card to discard in order to activate the ability.

Nuances:

• This differs from effects where discard appears after "to" or uses "then" phrasing, where the discard would be part of resolution rather than a cost
• When discarding is listed as a cost, you must be able to complete the action for the cost to be paid
• If you have no cards, you cannot pay the discard cost, so the ability cannot be activated at all