i had the same situation last night..

the map is set up in delve from the 1st room 3 tiles large room with doors between the tiles

some delve room have all the monsters on the map from the start.. so "setup"
some spawn monsters as you go.. "not setup"
some have doors but still map visible behind them... "vague area"
opening doors sometimes triggers events

so to me opening a door is a trigger and the the rules say if a trigger happens place the whole group..

a Boardgamegeek threed on same topic currently is concluding, opening the door is setup.. i disagree


Delve map in questions
10 7 and 12
was the garden patch one ice room and fire room one i think...

1st start/set up tile had the bane spider then a door had this been kobolds in this room to me the setup stage i'd have only done 2...kobold masters


RTL campaign games... when you open doors you tend to place map and monsters so again a "setup phase"

i'd argue because the map is already setup its not a setup phase but a trigger action that brought the Kobolds on...

whos right?

unable to find kobold text for this post right now...

but along the lines on during setup place only masters.. any other trigger place the whole group

I know...FFG defined very poorly the difference between Quest and Stage in order to apply some effects...like this one.

I didn't catch which posture are you with Milarky hehehe but, I support the side that says that Kobolds respond to a trigger.

I look at this problem like this:

1.- If Kobolds appear on either the Monsters Track or the map before any hero takes a turn , they are part of the Set Up, thus, only masters should be placed.

2.- However, if Kobolds appear on either the monster track or the map after a hero has already done something , then they are part of a trigger (event, door, etc), thus, they are all placed

[edit]: This is the text that modifies "Small Beginnings and Spawner" in RtL (it can be found on the skull [info pannel] of the Kobolds):

Kobolds spend [surges] in the following order:

[surge]: Swarm

Spawner : Because there is no overlord turn, "Spawner" places minions at the start of the Kobolds' activation instead. Place the minion Kobold in an adjacent space that is the closest to the closest hero.

Small Beginnings : Minions are not placed when setting up a new area of the map. However, if a group is placed outside of setup (such as at the end of a round or after interacting with an element on the map) place the minions.

As you can see, it says in "small beginnings" that minions are placed only if an effect (such as peril) or a quest effect (such as an objetive token or a door) says so...otherwise, they are not placed until the Kobold group has been activated.

I hope I was clear I will re-post this on BGG too