Loot Takedown saves you from stopping to search bodies; the loot comes to you as soon as the enemy goes down. One point after Sequence 1.
Loot Takedown sits at position 8 of 19 in the Stealth tree. Unlocking Loot Takedown takes 1 skill point. You need to complete Sequence 1 before you can buy it. Jacob and Evie each have their own skill tree, so you buy Loot Takedown once for each twin.
Air Assassination
Drop onto a target from above and kill him in a high-profile strike.
Assassin Steps
Greatly reduces fall damage, silences your landings and makes your movement much quieter.
Chameleon
In Sneak Mode, Evie becomes invisible while standing still; only enemies very close by can spot her.
Double Assassination
Kill two nearby unaware enemies at the same time.