Situation as follows

Opponent A has Frey hospitatlity PLOT card

Opponent B attacks opponent A with an intrigue of STR 1

Opponent A defends with Bronn with STR 3 and deadly

Does Frey take effect before Deadly ?

Both are passives, and so both will initiate after claim happens. The First Player will decide the order in which the passives occur. If Bronn's happens first, then the attacking player is gonna lose his attacker and one other dude. If the plot happens first, the attacking player would be wise to choose to lose his attacker, so Bronn's ability has no target (I'm assuming there's only one attacking character).

It depends on who the first player is. Both Deadly and the resolution of Frey Hospitality are Passive effects. The first player gets to choose the order that they resolve.

The order does actually make a difference if there are additional characters on the board for Player B.

The first player must decide which effect triggers first.
If the first player chooses for Frey Hospitality, then Player B can choose and kill the participating character. Then there will be no character remaining to satisfy Bronn's passive ability.
If the first player chooses for Bronn's passive ability to go trigger first, the only participating character for Player B will be killed by Bronn(unless saved), then Player B must choose a different character to satisfy the Frey Hospitality kill effect.

From his story, my understanding is Player B lost the INT challenge to a defending Bronn.

This is what we thought and how we have applied

Thanks