Hidden
A Hidden spell says “a unit”: can I choose a unit at any location?
Hidden adds a location limit to printed targets
RiftPal explanation · Answer first
Actually
When played from , a spell’s TargetA specific object, player or zone chosen by a spell or ability under the targeting rules. Check legality when choosing and when resolving. Costs, automatic groups and explicit "pick" choices do not target; pending Chain items cannot be targeted.View in Glossary must normally be at the BattlefieldA Battlefield is a shared location that players compete to control during the game.View in Glossary where it was hidden. The printed target requirements still apply.
RiftPal explanation
Why it matters
A target may be elsewhere only when its own explicit restriction makes choosing it at that Battlefield impossible. Having no legal local target is not an exception; you cannot play a spell from Hidden without its required legal targets. Non-targeted instructions keep their normal scope, and making new choices later does not remove Hidden’s location limit.
In practice
At the table
Back Off hidden at Battlefield A can StunAn action that makes a unit Stunned: it contributes no Might to combat damage, but its Might is unchanged and it still takes damage normally. Stun does not Exhaust the unit or automatically disable its abilities. The status is removed during end-of-turn Cleanup.View in Glossary a legal unit at A. Its plain choice of a unit does not let you select one at Battlefield B instead.
Card example
Back Off
Back Off’s unit choice has no explicit other-location restriction. When played from Hidden, choose a legal unit at the Battlefield where it was hidden.
Spell
Back Off
[Hidden] (Hide now for [Rainbow] to react with later for [Energy 0].) [Action] (Play on your turn or in showdowns.) [Stun] a unit. (It doesn't deal combat damage this turn.) If you played this from your hand, draw 1.