Required abilities to unlock and acquire:
from the Hunter Ability tree
Archery Master level 10
Overpower Bow Strike level 16
from the Warrior Ability tree
Overpower Attacks level 16
If you want this ASAP, get the level 10 ability then save your level 15 ability point for when you hit level 16. Then acquire both Overpower abilities. (Or, instead of banking a point, you can respec the ability tree at a small cost of drachmae.)
Required weapon types (you do NOT need Unarmed):
Some people say you don't need the other types, but if your trophy doesn't pop, then use these
There is an Overpower Attack for Unarmed, but you do NOT need Unarmed for the trophy.
Collect all the weapon types you need and make sure you perform an Overpower Attack with each one. You need at least 3 Adrenaline meter units to pull one off. Use
to initiate the Overpower. Keep landing normal attacks or assassinations to refill your Adrenaline.
video by PowerPyx on YouTube: