Can I use a card that requires me to block, to untap against an action that is directed at someone else?
No. Cards which require a block attempt as part of their untap effect (2nd Tradition, Eternal Vigilance, Speak with Spirits, Special Report, The Mole, Black Sunrise, Eluding the Arms of Morpheus, Sense the Savage Way) cannot be played if your vampires cannot block the action. If you want to block an action that is directed at someone else, you must first play an Eagle’s Sight or Falcon’s Eye before playing a card that untaps you and requires you to block. In other words, you would first have to play a Wake with Evening’s Freshness or Forced Awakening, then play the Eagle’s Sight or Falcon’s Eye to gain the ability to block, then you could use the untap and block cards.
