....when facing across the field against five abjurers and five feathered serpents? I'm not sure there's a single combination of units that has a prayer against that 4,000 credits worth of support units, especially when they're supporting indestructible infantry and cavalry? Even a hydra-changeling-mourner army didn't have a prayer. Maybe some kind of inorganic army, with an artificer to support it, but those armies tend to be broken down rather easily by faster moving organic armies.
Click surrender.
I've beaten that setup before(two changelings, sergeant, hydra, acolyte, strategist), but it wasn't worth the time.
Against 5 abjurer + 5 FS,
1 artificer+ 2 Golems/wyvern will win it for ya. There are a few other ways too, but involves cooperative mode.
Just got into another game... Fourteen Feathered Serpents so far, and four Abjurers, not counting the two I got on my side with the help of the changelings.
1 changeling, grab the abjurer, and start unsummoning. Wash, rinse, repeat for a few turns.
Alchemist helps too, but you need a big aresonal of action creators and stalling units like yes, changeling.
Hydra changeling, just start stealing serpents, sure he'ss unsummon them but then you can just summon them back atyour castlerins and repeat until he runs out of serpents