Yes, one of the hundreds of generic soldiers that went to kill freeman and had no real impact on the overarching plot in any way with the exception of one nuke.
Just because it was an expansion, and one you liked doesn’t make it important to a story. There are plenty of different fictional stories that aren’t canon, and they are enjoyable in their own right, but that doesn’t mean it’s important enough to just make it a part of the main story. NOT EVERYTHING IS CANON.
I’d make a half-life 2: opposing force mod. You’d play as Shepard as a Combine during the events of the slow-teleport through till the citadel explodes, if only so I can have him killed in the explosion. In fact I’d have you in the citadel when it explodes, and a message on the screen saying that you died before rolling the credits just so I can say that I killed the fucker off.