I might as well post what I've thought up for the Sultai so far. It definitely needs some work, and I've done my best to annotate it:
(You can tell this picture has been heavily pixellated)
Sidisi: Sultai Brood - (Delve)*
Units move through marshes and jungles at normal speed. Upon being defeated in combat, Sultai units provide
gold equal to twice their combat strength.**
UU: Rakshasha
Replaces Great Prophet. Cannot travel through borders without open borders.*** When a religion is spread to a city by a Rakshasha, every combat unit within a 1-tile radius becomes a Sultai Zombie.****
UB: Necropolis*****
Replaces Garden. Does not require fresh water. Adds +1
gold to each Jungle and Marsh tile.
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*Delve is sort of a generic name. I'm considering changing it to "Doom of the Golden Fang", hopefully with different connotations than Tasigur.
**Just to clarify, the Sultai get this gold, not whoever defeated the unit
***If I'm not mistaken, this is a promotion Missionaries and Great Prophets get. I should be able to turn it off just by removing the promotion.
****This does not include troops inside an enemy city or Sultai troops. I can foresee a problem in which this action could result in a worker being captured by the Sultai. This could be solved by respawning the worker in the nearest empty tile, or by just giving the worker to the Sultai, as if this ability wasn't overpowered enough. A Sultai Zombie's Combat Strength would likely be scaled by time, although it'd be nice to have a suicide squad that gives you a nice lump of Gold. I might make them weak but have them provide extra gold when defeated.
*****The generic boring building. As always, suggestions for this are appreciated.