Ooooh, now that's a tricky one. I went ahead and pulled a few rulings out of RONIN to examine (gotta love RONIN, it truly rocks...) here are a few I thought pertinent:
"¢ When you have a monster equipped with "
Metalsilver Armor", your opponent CAN activate "
Reinforcement of the Army".
"¢ When you have a monster equipped with "
Metalsilver Armor", your opponent CAN activate the effect of "
The Thing in the Crater" because it Special Summons a monster from your HAND.
"¢ Your opponent cannot activate "
Monster Reborn" and other cards that target while you have a monster equipped with "
Metalsilver Armor". Your opponent can activate "
Raigeki", "
Mirror Force", and other cards that do not target.
"¢ If you have "
Metalsilver Armor" active, your opponent cannot target his/her monsters either (with Equip Spell Cards, etc.), including with "
Premature Burial".
Now a couple things to note:
Premature Burial,
Monster Reborn are spell cards that are activated on the field and are targeting a monster in the graveyard.
The Thing in the Crater is an effect that activates in the graveyard and targets a card in the hand.
Reinforcement of the Army is a spell card that activates on the field, but targets a warrior in the deck. This may be a "loose" targeting since it is only looking for warriors in the deck. Similarly
The Thing in the Crater seems to be a "loose" targeting since it is looking for pyro monsters in the hand.
Taking these things into consideration, I would think that
Night Assailant's effect is A) activating in the graveyard and B) doing a "loose" target for flip effect monsters in the graveyard, so it would be able to resolve since it is out of the scope of Metalsilver's control.
As for
Vampire Lord, its effect is activating in the graveyard to revive itself, so it isn't "targeting 1 monster" in the formal sense and can revive itself.
That's my 10 bits on the issue. Any other thoughts?
