So as always not a game passes by without some questions
I was playing Greyjoy in a melee game and one of the opponents played Stark. I had my opponents discard cards from their decks and Stark discarded a Stalwart character (Midnight Sentry). I then played River Raid: Response: After a character card is discarded from an opponent's deck, put that card into play under your control. At the end of the phase, return that character to its owner's discard pile.
So after the phase was over i proceeded to return that character to the owners discard pile. Stark player said that it should be put on top of his deck as it has been in play and the keyword would change destination when leaving play to the top of the deck.
While my argumentation was that the text of the event should be followed it made some sense what he said. We ended up having him put the character on the top of the deck.
Was this correct or should the character end up on the discard pile?