Limited — once per game. During your play phase, every other character in turn order must use an Attack on the character nearest to them, or lose 1 HP.
Jia Xu is a fortress of tempo. Veil is a blanket immunity to black trick cards — the bulk of the deck's targeted scrolls are black, so Duels, Steals, Dismantles and Fire Attacks mostly slide off him, and opponents must burn their rarer red copies to touch him at all. No Quarter turns his own turn into an execution ground: anyone he brings to the brink can only save themselves, with no ally Peach, no First Aid, no Rescue to intervene — so his kills stick. He is punishing to remove and lethal on the offensive. His weakness is that Veil is blind to red tricks and to every basic Attack, and No Quarter does nothing on defence — a table that simply beats on him with Attacks, or waits out his turn, gives both skills little to bite.