if a leader is "coincidentally" present at a battle or a mission being attempted, can i use them? or rather; do i have to? Or do only the leaders, that are assigned to the battle or mission in question count? by this i mean the assigned leader(s) attempting the mission or activating the system for the battle and opponents leaders that are assigned as "opposers" of the given mission or battle.
Does this make sense? : )
lets say I'm dark side and vader ends up doing something on naboo. then later that same turn a attack naboo with a diffenret leader. can i then use vader who is "coincidentally" there (by my homegrown terminology here) in that battle?