Is there a way to effectively use Knifes and not be detected in late game stages?

Question

In the beginning of the Assassin's Creed 2 games (at least 2 and Brotherhood, not sure on Revelations) your throwing knives can be used to kill guards and not be detected however as the game progresses you knives tend only damage them.

In missions where you aren't allowed to be detected (or it being a secondary objective) if the guard doesn't die in one hit, even if they are killed by a second knife throw about 1 second after the first was thrown the guard is alerted just at the moment the second knife kills him, causing de-synchronization (or failing of secondary objective).

Now considering that at these later stages you can buy upgrades to your knife pouch i am wondering if there is an effective use for Knifes? preferably to kill a target in one hit

Answer 1

One thing you can do to kill higher level enemies is to train at the Monteriggioni villa. This will let you throw up to three knives at once. Now, you can hold down the throw button to "charge" the attack, but when you let go you will instantly kill the enemy. Of course, you can also use this to hit three enemies at once.

Answer 2

Armored guards are only damaged by throwing knives, especially during combat. This is true. The distance is also quite limited. But there are always alternative weapons and methods that can be used: smoke bombs or poison blades for example. Or simply monitoring the patrol patterns and striking when opportune.

Especially in Brotherhood, during stealth missions you should always consider using the crossbow! The crossbow kills instantly and has a quite impressive range. It is quite costly, but definitely worth the investment. As long as you are not observed killing the guard, it is even possible to kill a guard in the field of view of another, since he will walk over to his buddy to investigate.