Forewarned

[hrcho]

This is the situation:

- both me and my opponent are playing besiegers as shadow
- he is playing elves as freeps.
- he has many minions stacked on a site he controls and I have many minions stacked on a site I control
- the top card of his draw deck is Olog-hai of Mordor
- my very powerful troll is skirmishing his not so powerful elf
- he plays Forewarned and reveals OhoM from the top of his draw deck

What now?

What is the twilight cost of OhoM? I understand that he cannot spot his shadow cards and stacked minions, but he can spot mine and it's not a voluntary action. I think his OhoM costs  (if 5 or more  minions are stacked on a site I control) but I'm not sure, thus the question.

[Witchkingx5]

Might of the Elf Lords, hm?

Well, I think that the Twilight costs are 10, cus' as he's the Freeps player, he can't use Shadow abilities to spot anything.

[Smeagollum]

I guess you're referring to Forearmed. The anwser is the same as wk555, but more because the text is only active when you play ohom. So you can't use that text. So using forearmed will make it minus10 in this situation.

[hrcho]

I did mean Forearmed 

Well, I think that the Twilight costs are 10, cus' as he's the Freeps player, he can't use Shadow abilities to spot anything.

That's the problem, that is not a special ability and it's not voluntary, as I said. However, as Smeagollum said and I now think he is correct, OhoM text is not active if the minion is not in play.

Although, just for the discussion's sake, Forearmed looks for the cards twilight cost and the card has a text that modifies its cost which means that Forearmed could activate that part of the text.  
What about Ulaire Toldea, WoW? I believe there was a similar discussion about Southron Invaders being able to pull Foul Horde from the discard pile but I don't know its conclusion.

Anyway, this brought up another question for me:
If a player controls a site, can that site be spotted by another players shadow cards (in a 2 player game)? The manual only says that the text of a site cannot be used by any player (Exception: Keywords), but it doesn't say anything about spotting that site. Shadow cards are not active, but sites are not shadow cards, although "to control a site" might mean to make that site a kind of a shadow card. For example: Ulaire Nelya, LoM desperately  wants to spot a site but that site is being controlled. Can he spot it?

[TelTura]

the manual says under "active" that sites in any player's support area are still in play.

During your turn, only these cards in play are active:
• sites on the adventure path,
• sites in any player's support area,
• your Free Peoples cards,
• your copy of The One Ring, and
• your opponents' Shadow cards.

and under "spot" it defines what it means to spot something:

The word spot sets up a requirement for playing a card or using a special ability in conjunction with a noun such as, "To play, spot an Elf." This is equivalent to, "An Elf must be in play and active for you to play this card."

so, seeing as the site is in play and active, I would imagine you could, even if it was that player's fellowship phase.  And you could then use his special ability as per this section under "control":

Some cards can replace a controlled site. Move any cards stacked on the site being replaced to the new site, then return the old site to its owner's adventure deck.

[legolas3333]

Forearmed and Might of the elf lords only activate the twilight cost, same with catapult, the discussion on Foul Horde was resolved by saying that Southron Invaders only activates Ambush not text that would make a minion gain ambush. As for your Nelya example, the situation is impossible as there was no site control in FotR block and he can only replace FotR sites.

[TelTura]

can't he in open format, at least?  he doesn't say "Site 1" or anything, just a generic "site".

[legolas3333]

uh read the clarification on his card page

[TheJord]

Twilight costs are only modified when a card is played

[Kralik]

can't he in open format, at least?  he doesn't say "Site 1" or anything, just a generic "site".

Decipher has specifically stated that it only works in FotR block.

[hrcho]

Thank you all for clearing that up for me.