I praise that knight for staying silent in her her blind spot when going for the kill instead of yelling and revealing his presence
Right, but I'm sure this violates some manga law or something.
When ambushing someone, you're supposed to yell something, preferably the name of your special attack.
"Silent Knight's Invisible Strike of the Hidden Blood Moon of Twilight".
The longer the better. Also, the cringier the better.
No wonder he died. We can't have that kind of criminal backstabbing people in a way that actually makes sense.
(Edit: Actually, I'm not sure he died. It's not very clear but I think the armor took most of the damage.)