"Desolate passage" and "Walder Frey"

[Calepin 0]

First, the cards :

 

Desolate passage : Each player cannot declare more than 1 attacker or defender in each challenge.

 

Walder Frey : After at least 1 defender is declared during a challenge, kneel Walder Frey to have him participate on the side that is currently winning the challenge.

 

So, if I understand the meaning of these two cards, Walder Frey will join the attacker of defender because he haven't been declared as an attacker, i'm I right ?

[-Istaril 157]

Yes