by Becq
Rich's answers are accurate. If you found the enmity cost to be too low in the case you mentioned, it's likely to be because of the rule Rich stated.Note in general that anytime you feel an advisor is too powerful, you should keep in mind two balancing factors:
1) Advisors can usually be used only once per game year.
2) Some advisors may look powerful, but can only be used in very limited circumstances.
3) If you still think an advisor is too good, then you can always steal the advisor!