Respond with an on guard that creates an effect (later)

[Alter Tuk]

Hello my rules-gurus,

I know that in a chain of effects I may not respond with a card that creates an attack. What about the following situation?

Hazard limit is 2. My opponent moves to the Lonely Mountain. Gates of Morning is in play. I play Itangast ahunt. Opponent responds with 2 Many turns and doublings to reduce the hazard limit by 2. I respond and put Smaug on guard. May I reveal it in site phase?

I`d say yes cause it starts a new chain when its revealed but I want to be sure.

Thanks in advance,
Took

[Balin]

As far as I know, on guard cards can't be played in response.

[Bandobras Took]

# Annotation 15: An attack must be the first declared action in a chain of effects; i.e., a creature card may not be played in response to another card in the same chain of effects. Revealing an on-guard creature is an exception.

# @ Any card that has the potential to immediately create an attack is considered an attack for purposes of interpreting Annotation 15. [CoE] %

Playing a card on-guard does not create an attack within that chain of effects and so is legal, so far as I know. I can't find any rule which forbids the playing of on-guards as an action in a chain of effects, but I might be missing something.