This mod only feeds my love of the Arcane tree. I only have one thought about something that may cause problems, the destroyer and protector promotions. If you have them rigged like the normal immortal promotion they will be lost on death.
OMG, I just saw this comment. This is definitely an issue, but I think I'll leave them as they are. An alternative could be making them the prerequisite of the Immortal promotion, so that arcane units that have Destroyer or Protector can purchase Immortal on level up, but I think the current implementation is more fun.