It’s Harry, he too is a champion of the White God, but on a different mission, one for which the swords are not always suited.
In Battle Ground the swords were in play not to defeat Ethnui but to prevent Harry from murdering Rudy, and removing Harry’s capacity as a champion for the White God. Harry was therefore able to beat Ethnui.
This leads to the question of who exactly was behind Rudy and whether it was infernal in nature, as Uriel can only act where there has been an infernal influence. Namshiel was in play the only one of the Fallen involved in Battle Ground, but there is no indication he influenced Rudy.