The idea of a pacifist monk is interesting (I'd push for Ullar rather than Aquilla for it), but I see some problems with the current direction.
Removing Order Markers can be very unfun to fight against. If there isn't some way for the other army to counterplay against it (or if it isn't significantly limited such as with the Fyorlag Spiders' Entangling Web), it can just be downright frustrating to lose out on a ton of turns. Limiting it to a defensive response is a neat idea, but you run the risk of losing the rest of your turns if you whiff a single ranged attack.
Personally, I'd first suggest limiting it to melee attacks only. I admittedly haven't seen
Daredevil, but it feels more thematic to me for him to only be able to neutralize figures within striking distance rather than through some sort of superhero-esque feats against distant attackers. Thematically, I also think that it should be limited to Unique Heroes, or else he could knock out one Knight of Weston and suddenly the entire army can't move as a result.
Here's some quick off-the-cuff brainstorms for more limited versions of the power, to give some ideas:
Instead of attacking with Sajan, you may roll the 20-sided dice. If you roll an X or higher, remove any number of unrevealed Order Markers from this Army Card. You may remove up to the same number of Order Markers from the Army Card of any adjacent Unique Hero.
After rolling defense dice against a normal attack from an adjacent Unique Hero, you may remove an unrevealed Order Marker from both this Army Card and the Card of the attacking figure.
After rolling defense dice against an adjacent Unique Hero, you may roll the 20-sided die. If you roll an X or higher, you may remove 1 Order Marker from the card of the attacking figure.
The first two share the requirement to remove Order Markers from Sajan's card to neutralize others. This stops him from potentially deleting an opponent's round after a lucky roll, but still lets him stall if you want to give up more than your X in a round. It still runs the risk of being unfun to play against, but there's more room for the opponent to avoid it with these kinds of limitations.
For the last idea, I'd suggest a high roll (15 or higher) because it's not limited and could prove to be very strong in clean-up. Notably, if Sajan is a monk, he's going to get synergies with Master Lao Xin, which gives him more freedom to move without losing out on too much offensive power while getting him into position.