While a side quest is in the victory display, Rider of Rohan does not exaust to quest.

"Who are you, and what are you doing in this land?" said the Rider, using the Common Speech of the West...
–The Two Towers

Response: After Fastred defends an enemy attack, return that enemy to the staging area to reduce your threat by 2. (Limit once per phase.)

"King's man! King's man!" his heart cried within him.
–The Return of the King

Play only if you control a unique character with the Rohan trait and another unique character with the Gondor trait.

Response: At the beginning of the combat phase, you resolve the step in which you attack enemies before resolving enemy attacks this phase. (Each other player resolves the combat phase as normal after you resolve your attacks.)

Response: After Riddermark Knight is declared as an attacker, it gets +2 for this attack. At the end of this attack, discard Riddermark Knight.