1.
I'm not going to say "where does this leave us" but instead "where it was started".
Rules Erratum: An on-guard card may only be revealed if it could have also been
played during the movement/hazard phase. This means all targets of the card must
have existed during the movement/hazard phase in order for the card to be revealed
"All targets of the card must have existed during the movement/hazard phase" is no the same as "the card must have a target existed during the movement/hazard phase". First checks whether it was playable on the same target in both phases, second only whether it was playable at all in both phases.
It is not mentioned "in which M/H phase" (as though only one was possible). In that M/H phase where on-guard was placed? In last M/H phase (when the site was moved to [only relevant for companies that moved])? In all/any M/H phase(s)? Not sure (at least at this point - see part 3) .
One sure thing is: if something appeared in site phase then it did not exist in (any) M/H phase.
At best in M/H phase something identical could exist .
How to handle situation when "something" is unique card like The Mouth?
Suppose that The Mouth leaves active play and then is played again yet in the same M/H phase. Previously he was under effect of Orc-Draught, a corruption card was played on him in that turn and he was wounded by Undead.
If now returned to play The Mouth is not under effect of Orc-Draught, a corruption card may be played on him, but Endless Whispers may not, then it is considered as new character. He has old identity but new history.
In other words: for rules that refer to "that character" The Mouth removed from active play and The Mouth returned to play are not the same character.
2.
Targets.
If some texts refer to target I assume that it says about "valid target" (unless specifically mentioned otherwise). I'm wrong in this assumption?
Whether if some text says that card targets X, then it says about both valid and invalid X?
3.
I'm deliberately avoiding a phrase "playing on-guard cards". They are not played, at least not in M/H phase; only placed.
Please note that on-guard card as indicated by its avers may be even character, or resource - something that cannot be played at all in M/H phase.
And what is sometimes called as "playing on-guard" is not handled by rules like playing a card.
CRF, Errata (Cards), Deeper Shadow wrote:Card Erratum: This is a short-event, not a long-event. Deeper Shadow can cancel
hazards by reducing the hazard limit to the point where the hazard resolving is no
longer playable. If this is done to an on-guard card, the card is returned to the player's
hand. The character must be moving to the site to change the site type. This works
even though the site is not technically part of the site path.
The character must also be moving to lower the hazard limit.
*
Underline mine.
If declared card cannot resolve for any reason it is discarded. It does not happen in case of on-guards. Because what is declared is a placing a card and if this action cannot be resolved the placing cannot be done. (Similar but reverse situation: if there is not enough HL at resolution, declared returning to hand Spider of Morlat cannot be done, Spider remains on table).
Why I'm writing about that here: because "placing vs. playing" translates on my interpretation of situation.
In M/H phase an on-guard card is not played but placed on site card.
I cannot find indication in rules that on-guards placed on the same site card are distinguished on any basis (I do not preclude such possibility, I just says that there is no indication known to me).
If actually there is no such distinction a question "how was a state of things in M/H phase when card was placed" is irrelevant. Only identifiable M/H phase that has anything in common with site card where on-guard was placed and with company at the site is the last company's M/H phase.
*) Why to the heck it is not stated in CRF, Turn Sequence?
EDIT:
Changed:
"Only identifiable M/H phase that has anything in common with site card where on-guard was placed is the last company's M/H phase."
to
"Only identifiable M/H phase that has anything in common with site card where on-guard was placed and with company at the site is the last company's M/H phase."