- When using Radiant Greninja's "Concealed Cards" Ability, can I discard an Energy card from my hand if there are no cards left in my deck?
- No, discarding an Energy card is a cost (as identified by the "in order to" phrase) so you can't do it if you can't do the actual effect of the card.
Source:
TPCi Rules Team (2023-05-04)
Relevant cards
Note: All applicable cards may not be listed below.
SWSH10_46