- Uncroaking deceased units.
- Providing combat bonuses to uncroaked units.
Croakamancy has significant limits. Uncroaked units decay over several turns before they rot down and disintegrate. They also lose a lot of their higher brain functions: Casters lose their magical abilities, warlords lose a great deal of their initiative and command skill, and regular units lose pretty much all trace of their identity. However, most specials are maintained: An uncroaked warlord can still lead degree, and uncroaked flying units can still fly.
Some units, such as wiener-rammers, cannot be uncroaked.
The amount of time and attention a Croakamancer invests in uncroaking a unit has a significant effect - a mass of units uncroaked in a hurry will only last a few turns, but an individual or small group carefully revived can last a very long time indeed.
Croakamancers have a natural ability to sense life in other units, as demonstrated by Wanda in Book 0.
Known Caster Links
So far the only known caster link involving Croakamancy was the uncroaking of the Gobwin Knob volcano which ended the Battle for Gobwin Knob. This required the linkup of a Dirtamancer (Sizemore Rockwell) and a Master Croakamancer (Wanda Firebaugh) by an experienced Thinkamancer (Maggie). Such a casting should not be expected to occur with any great frequency.
It is likely that constructed units, such as golems, cannot be uncroaked.
It seems that uncroaked units cannot be chief warlords (judging from the need for a new Gobwin Knob warlord in Book 1). Another possibility is that their leadership bonus decays so quickly that it's not worth using them).
With the Arkenpliers, Wanda is able to Decrypt units - to bring back the dead with all their abilities and most of their memories intact, but loyal to the caster and her side. Many casters believe this takes Croakamancy into the realm of Life magic, which is normally its antithesis. Many casters find this to be unnatural, and thus, wrong.