A new race/faction of cultists and demon worshipers would add a lot of atmosphere and variety to the game.
It would also be a chance to implement religion in some form which so far only exists in the game as references through the classes of monk, cultist ect.
Some ideas on enemy units
Cultist- basic infantry unit with low-medium grade weapons and equipment, possibly they could be difficult to route either through zeal to thier dark gods or even more so through fear of what would happen if they failed in an assigned task.
Cultist Zealot- Heavier infantry unit perhaps with a special ability akin to the orc berzerker’s rage skill, or some kind of unholy buff regen when they kill an opponent.
Heretic Priest – One option for leader of a cultist group. Wears only robes and ritualistic attire such as a headdress or mask. weak in melee but protected fervidly by his followers. Chants or other minor spells to effect the battle for example by raising morale/ damaging the morale of mental stability of enemies, or some cases even summoning deamons, which could take multiple turns and mean a race-agaisnt time for the player before the heretic priest calls forth some kind of ungodly beast from the void.
Minor Deamon/ Imp (choose better or germanic name than this) this small black or red-skinned and very evil form of deamon could have special demonic abilities such as spitting flames or causing explosions through some other means, would probably use similar tactics to goblins and employ skirmishing/hit and run style or trying to overwhelm individuals through numbers. low morale and would flee easily without leaders or when a battle turns against them. small and therefore able to escape from adjacent hexes much more easily than human-sized characters
Archdemon – An extremely dangerous and bloodthirsty type of daemon which can only be summoned through complicated and lengthy rituals usually involving some kind of human sacrifice. Highly unstable unpredictable – might disobey,turn upon and slaughter their own summoners. Difficult to kill in a similar way to orc chieftains and would possess demonic weapons giving their attacks extra effects for example draining stats, causing fear or burning wounds