The ability can be used when in torpor.
201672
Gathii
G7Anarch: During an action Gathii performs, you can reveal the top card of your library. If it is a master card, he burns 1 blood; otherwise, he gets +1 stealth.
Rulings
Can be used when stealth is not yet needed. Any stealth that would be gained is not gained (as no stealth is needed).