Steelrising

Firstly you'll need a gun or some sort of long range firing weapon as you need to hit the enemies BEFORE they see you and drop out of their hiding places. The easiest Prototype to farm these on are Stalkers and you come across them very early on. Assuming you found the chest containing the Charleville 1789 Shield Musket while trying to escape the Queen's Estate in the tutorial, the best and easiest place to farm this trophy is after rowing in the boat over to Paris.

You'll arrive in Paris outside the oh so lovely town of Gros Caillou, proceed along the main path until you reach the first Vestal in this area.

From the Vestal if you head a little up the path behind it you'll see a little fence on you right that's covered in Ivy and a little well in the courtyard behind the fence. If you look in the tree hanging over the well and press R3 to "lock on to target" you'll find a sneaky little Stalker hiding amongst the leaves waiting for you drop by for a visit.

Jump over the fence and shoot at the Stalker with your Charleville Musket (or whatever you are using) and shoot at it once to make it drop out of it's hiding place, then finish it off however you please.

Once the Stalker is dead, simply jump back over the fence and go rest at the Vestal to respawn another one. Rinse and repeat!

It's a slightly tedious way of doing it, but it's still relatively quick and enables you to get the trophy done and dusted very early on.

P.S. The same Stalker is also very good to use to farm other trophies like "The Aegis" (Block 50 attack impacts with a shield special move) especially if you are already using the Charleville Musket as it has the shield special move.