In this quest, can I play an overlord that states "when a hero attacks a monster" after a hero attacks the monolith.

"....a hero may attack the monolith as if it were a monster"

Is it worded like that to let the players know you can play OL cards in those situations?

I'm unsure of this one. To me, all that really says is the monolith's space can be considered by a hero to be containing a monster, and he can attack it as such. It says nothing about how the OL may treat the monolith. In fact, it would have been simpler (if the OL and heroes were both supposed to treat it as a monster) to just say "the monolith is treated as a monster" or that same phrase plus "for the purposes of attacks."

However, the phrase chosen only specifies what the heroes can do. Note that as it is a reanimate CANNOT attack the monolith.

There was a thread some time ago with a similar question about the rift crstal in into the dark... I do not remember if there was an FFG response.

Same happens on Heart of the Wild. We played it the other day, and I, as the OL, didn't play any cards on the Heart, arguing it was not a monster after all, but I let the heroes use "when attacking a monster" skills. I'd be very interested with the answer.

We never got to an FFG question, as it was about familiars (which I was pretty sure about.)
https://boardgamegeek.com/article/20329828#20329828

I can ask FFG to clarify the implications of the phrase.

EDIT: BTW, here's what I asked:

Any update?

Any update?

Not yet. I only submitted the question today after I got back into town.

Still no?

Still no?

I'll post the answer when I receive it. Honest.

a) Yes, hero abilities, surge abilities, and skills that trigger when you attack a monster may affect the objective token while it is being treated as a monster (that is to say, while it is being attacked). Hero abilities, surge abilities, and skills that target a monster must be used when the objective token is treated as a monster, that is to say again: while it is being attacked and at no other time.
b) Yes, the overlord may treat it as a monster during that attack and use cards that trigger “when a hero attacks a monster."

Thanks,
Kara Centell-Dunk
Game Developer
Fantasy Flight Games

Zaltyre's edit, not from Kara : That is, if it's occurring within the context of an attack, abilities that target "monsters" apply to that object. In other words, IF the objective token is being attacked, then WHILE that objective token is being attacked, everyone can treat it just like it were a monster.