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

Yeah, I imagined the bone legionnaires (Tier 3, Level 3) to look something like this.

My knights are somewhat similar to undead, but not skeletons – they have too much flesh on their legs and arms, but a possessed ghost as armor would work well.

Added 6 minutes later
There was a similar unit in the game about Iratus.