Must be played (as well as other "as the action is announced" action modifiers) before action modifiers that are not explicitly played "as the action is announced" (e.g., Conditioning).
101867
Stealth Ritus
Requires a ready Sabbat vampire. Only usable when the action is announced.
Choose another ready Sabbat vampire you control. The chosen vampire burns 1 blood, or this card has no effect. This action gets +1 stealth, even if stealth is not yet needed.
Rulings
Replace the action card (if any) before playing it.