Trinity comet deathblow

Trinity comet deathblow is Yeladot Shavit's finishing move that allows the three of them to instantly kill a single ace gauntlet knight.

Trinity Comet Deathblow (SS)

It's said that they've mastered specialized tactics that will allow the three of them together to instantly    kill a single  enemy Aerial Augmented Infantry ace. This sounds like an ace-killing finishing move, but it's rumored that this three-person attack would take out its users as well, so its true value is veiled in  secrecy.

Yeladot Shavit are also Barrier troops, meaning their job is to keep military discipline and to keep allied troops from fleeing the battlefield, with a threat of shooting them from behind if they try.

This is why in the Battle on Christmas Eve Yeladot Shavit uses Trinity Comet Deathblow to kill a treasonous ace: Naima.

We see that Naima decides to follow her own conscience instead of orders and she decides to kill anyone who tries to kill as a deterrent. 

Because of this Yeladot Shavit is ordered to take out a rebellious ally, which must be Naima since she's the only one we saw rebel in the ABN.