RTF is a global modification that replaces all towns in the game.

Hooray! Now I can type normally.

Hooray! Hooray! Hooray!

Regarding the Orcs. What is this "Dragon's Tithe"?

"Betrayal" is an interesting mechanic from the point of view of balancing individual units, as is the Hero who has a special ability related to it (Keegan, in the original).
But in the context of your Faction, I don't think it will be appropriate. Firstly, you can't implement Keegan's special ability here (since it also provides Tier 1 reinforcements for the Orc Horde), unless you swap the IDs for Orc and Human units so that it works on the intended units. Again, if the current Orc (Cult) Faction has a Hero with this ability, he will be almost unbeatable against the Orc Faction, because he changes the "betrayal" percentage in both directions (lowering it for his own side and increasing it for opponents), and at a high level, all your Orcs will start switching to his side with just one attack! 🤔
--- -- --
*In my mod, this mechanic is implemented through Perk Neutrals, Mercenaries. And for now, I think this is the most successful way to implement both the ability and the Hero's special ability.
*In the original game, as I think, neither "Betrayal" nor Keegan are fully implemented. Because "Betrayal" was only available for Goblins for the entire game, and obviously, no one plays with ordinary Goblins without upgrades beyond the first few turns, until they build a Tier 1 building in the city. Again, his special ability is given to Trappers, i.e., already upgraded and non-betraying Goblins.