Hmm, just as a thought.
Uncroaked can still gain levels - we know this because Stanley gets annoyed at Parson for attacking and withdrawing when taking down seige units.
Uncroaked do not cost upkeep - we know this because... well, its mentioned when uncroaked are being explained. They do however, have a Decay rate. From what the Transylvito troops sing when they fight Stanley as he's going to the FAQ ruins, even they decay, and they seem to be the 'basic' troop types of Transylvito at the moment.
Now... does -everything- that a city controls have an upkeep? Farmers like FAQ had? Miners?
These new type of uncroaked - The Decrypted, dont have an upkeep and dont decay. That doesnt neccisarily mean they are any more powerful then an ordinary basic/advanced/heavy troop other then the fact all they cost is magical power (which i'm assuming recovers in each caster at turn start like MP in most games)... Then the only real advantage is that they dont cost anything to make or upkeep. Presumably Gobwin Knob is going to need 'ordinary people' to keep it functioning and thats what the main bulk of those guys will be used for.
Hmm, not sure where i was going with that anymore. oh well