The Ninja perk improves the damage of both ranged and melee sneak attacks.”— Fallout 4 loading screen hints
With the first rank of this perk, ranged sneak attacks deal 2.5x normal damage and melee sneak attacks deal 4x normal damage. The second rank raises ranged sneak attacks to deal 3x normal damage and melee sneak attacks to deal 5x normal damage. The third and final rank causes ranged sneak attacks to do 3.5x normal damage and melee sneak attacks do 10x normal damage.
- To attain this perk you are only required to have an 80 Melee Weapons skill, even though the perk affects the critical bonus and sneak damage of both Unarmed and Melee Weapons.