Best Answer
How does Crown Regent interact with Marriage Pact and Secret Pact?
If Crown Regent redirects a challenge to Marriage Pact's controller, does attached character simply stop participating?
If Crown Regent redirects a challenge to Secret Pact's controller, what happens?
If Crown Regent redirects a challenge to Marriage Pact’s controller, the attached character is removed from the challenge. The “cannot participate†text is absolute, and prevents the character from participating in any challenge against Marriage Pact’s controller.
If Crown Regent redirects a challenge to Secret Pact’s controller, the attached character remains in the challenge. Secret Pact only prevents the character from being declared as an attacker against Secret Pact’s controller. Once the character has been declared as an attacker against the original opponent, redirecting the challenge does not remove the character from the challenge — the challenge is still considered to have been initiated (and attackers declared) against the original opponent.
[Danny Schaefer, 18.10.2018]