rocklikeafool
Warmaster
They aren't pact of nilhorn giants, they're entirely barbarian spawns.
And yeah, they're air elementals that are spawning. As well as a lightning elemental.
When I get back from holidays I'll go through the text file of the scenario tile by tile to ensure that there isn't anything hiding.
How many hill giants are there? If there's more than three, they're nilhorn spawns. As to the air elementals and lightning elementals, those are either from Barbatoes' magic or are bugs.
And, yes, check the text of your files.