Another player came up with this on cardgamedb rules forum, and we couldn't reach a conclusion:
"After you trigger an effect that kneels an opponent's character, choose and kneel 1 character controlled by a different opponent."
Harry the Riverlands:
"Kneel any number of characters with combined printed cost of 3 or lower."
Queen's Guard says "...kneels an opponent's character..."
So it doesn't apply if I kneel more than one with one triggered effect?
Queen's Guard says "...controlled by a different opponent."
So I can't kneel all the Refugees of all my 3 opponents and still trigger him, as it has to be an opponent whom I didn't kneel anything of with my triggered effect?