Powerful casters, like Necromancers, risk gaining insanity, which gives them a percentage chance to do nothing each turn.
For the most up-to-date community guides and discussions, check the Conquest of Elysium 5 Steam Community . Specific introduced in recent versions? Conquest of Elysium 5 v5.23
To put v5.23 in context, it sits between several major milestones in the game's lifecycle: Major Version Notable Addition risk gaining insanity
The editor was updated to display "typical snow coverage," helping creators better visualize seasonal terrain impacts during the design phase. Conquest of Elysium 5 v5.23