The Barriston Selmy who has the text "Challenges: While Ser Barristan Selmy is participating in a challenge, discard a card form your hand to choose 1 participating character. Until the end of the phase, that character gets -2 STR and is killed if its STR is 0." When does this resolve?
So I issue a challenge with two characters strength 2 and deadly, they defend with Barristan, throw a card away and kill my character. Does my character die and leave the game as part of the player action, or are they moribund until the end of the challenge? i.e. I win the challenge, and have more deadly characters so would kill Barristan and get my claim? If I had the ability to raise their strength to more than 0 could I do that to save them or are they moribund before I can raise their strength? Or does my character die on the spot, and I now lose the challenge. Would the dead character's deadly still apply?
How about in defence? Would the challenge be undefended if the character had been killed in the player action before resolving the challenge, or are they still considered to be contributing their strength and die after the challenge resolves? If I am defending and losing a military challenge can I select the same character to satisfy the claim?