https://whc-cdn.games-workshop.com/wp-content/uploads/2017/07/Warhammer_40000_Stepping_into_a_New_Edition_of_Warhammer_40000.pdf wrote:Q: Do models with profiles, such as Armorium Cherubs and Ammo Runts, count as a model for the purposes of embarking within transports or when measuring ranges to and from the unit?
A: Yes – for all rules purposes they are part of the unit.
Because the Watcher in the Dark that carries Azrael's Lion Helm does not have a profile, it doesn't take up a transport slot. However Armorium Cherubs do have a profile, so do take up a transport slot.