Assuming no other effects, if the The Red Viper (PotS) attacks and Bronn (LotR) defends is the The Red Viper immune to the "reverse" kill effect. The effect is a passive and not a "keyword" and so at a first glance it looks like he is immune but Bronn's ability targets the player and not the red viper so what really happens?

A bit confusing also if Bronn defends against Joffrey Baratheon (TftRK) what would happen?

Reager said:

To dispel a misconception you voiced, though, Bronn's ability does not "target" the player. In this game, the target(s) of an effect are whatever the effect specifically says to "choose." If the word "choose" is not used, there is no target. If the word "choose" is used, only what is chosen - as opposed to who does the choosing - is targeted. Bronn does not say "choose the attacking player," so his ability does not target the player. It says that the attacking player chooses a participating character, so the character is the target - even though Bronn's controller is not the one doing the choosing. Note that even if Bronn's ability did say to "choose" the player, if it also said "that player chooses and kills a participating character," the ability would also target the character. Anything and everything that is specifically "chosen" by the text of the card is a target for that card. (And things that are immune to that card cannot be chosen.)

Note, however, that even if the attacking player was chosen/targeted and the character was not, immunity to character abilities would still protect The Viper. That's because players do not kill characters; rules or card effects kill characters. Not that it ever would, but even if Bronn said something like "choose an attacking player to kill a participating character" (so the player is targeted but the card killed is not), it would still be Bronn's resolving card effect, and not the player, that is considered to be killing the character. Since immunity allows the card to ignore the direct effects (such as being killed by) whatever it is immune to, "immune to character abilities" would protect a character from Bronn's ability, even if it wasn't targeted.

So, to sum up: Bronn's text is a character ability that targets an attacking character (not the attacking player) and kills it. While it uses the presence of a keyword to determine its play restrictions, it is the character ability itself that initiates and resolves to do this. So, immunity to character abilities will protect from Bronn's "reverse Deadly" kill effect.

Reager said:

thanks, perfect explanation as always