Challenges: If it is Summer, kneel 2 influence to choose all participating, non-Dragon characters. Until the end of the phase, each of those characters gets -2 STR and is killed if its STR is 0.
I just want to make sure I'm reading this correctly. This effect would only apply to cards currently participating in the challenge, any cards which became participants in the challenge after Field of Fire was played would not be affected, correct?