I've just encountered my first Elite guard. My companion says something along the lines of "That guy looks tough, you may not be able to take him down even if you catch him by surprise. You'll have to stun him somehow first." Looking in my bag of ninja tricks, I couldn't come up with a way to "stun" him other than beating the snot out of him, which obviously attracted his attention. Is there anyway to kill him silently?
Elite Guards are the first of a couple of different types of enemy that are immune to instant-kill quick-time-event attacks.
That said, you can "stun" them and then instant kill them with certain equipment:
- Caltrops (although they must walk over them)
- Spike Mines (again, they must walk over them)
- Smoke Bombs (only if upgraded with the "choking gas" ability)
You can outright kill them with:
- Upgraded terror darts (terror dart FTW!)
- Ravenous insects, although this can be somewhat attention-getting to other enemies in the area
You can also lure them into traps or drop environmental objects (ie, chandeliers) on them to kill them. Or you could terrorize nearby guards and get them to attack everything, including these guys. I don't believe they themselves can be terrorized, though.