103.2 If a modifier says that [something] can’t happen, and another modifier or rule tries to make [something] happen, that “can’t” modifier takes precedence (but see 103.3). If an action can’t be performed, any cost involving that action can’t be paid. “Can’t” modifiers are not replacement modifiers (716). Events that “can’t” happen can’t be replaced
709.2b If the link has not been interrupted, resolve it. To do so, its controller must process its text in order. If a link tells a player to take an action, that player makes all choices for that action that were not already made, and can’t choose to do anything that can’t be done. (in this case destroy a wotf ally)
From FoH FAQ
· Will of the Forsaken
Charkov, 5, Horde, Ally—Undead Priest, 3 [Shadow] ATK / 4 Health (Honor-123C)
Will of the Forsaken (This ally can't leave play unless it has fatal damage or 0 health.)
When Charkov enters play, each player puts an ally from his party into its owner's hand.
Sivandra Darklust, 3, Horde, Ally—Undead Warlock, 3 [Shadow] ATK / 3 Health (Honor-146C)
Will of the Forsaken (This ally can't leave play unless it has fatal damage or 0 health.)
When Sivandra enters play, draw a card, then destroy an ally in your party.
Example: Late in a game, your opponent controls one ally and you control none. You play Sivandra Darklust and draw a card, but she can’t be destroyed because she can’t leave play. Next, you play Charkov. Your opponent must put his ally into his hand, but neither of your allies can leave play. You can’t pay costs requiring you to destroy either of your allies or otherwise remove them from play. If either of your allies is Hibernated, it enters your resource row (because that’s not leaving play).
Only two things are infinite......