1. What is the definition of "in territory" in Redemption?
2. Does the Crimson Rehoboam have any errata?
"In territory" basically means "the territory of the controller of this card, unless another player is being referred to". That's my wording, not REG wording (if there is REG wording).
So that's why the Crimson Rehoboam can only target heroes in your own territory, because it says "in territory" (not "in a territory", which would mean the same territory but could include your opponent, or "in territories", which would let you target any two heroes in any territories).
