Iron Fist

Iron Fist is a perk in Fallout 3, Fallout 4, Fallout 76 and Fallout 2d20.

Effects
Each time this perk is taken, it increases Unarmed damage by +5 points.

Bugs
Upon unlocking rank five, critical hits in V.A.T.S. while wearing power armor will no longer function; the Sole Survivor will simply stand idle while no animation is played or AP is consumed.

Effects
Iron Fist is a perk in the Nuclear Winter battle royale mode.
 * Nuclear Winter

Modifies weapons
Iron Fist affects the following weapons, as well as their unique variants:

Fallout 2d20
At rank 1, unarmed attacks inflict +1d6 damage. At rank 2, unarmed attacks also gain the Vicious damage effect.

After rank 1, the level requirement increases by 5.

Behind the scenes
The perk alludes to the Marvel Comics character Iron Fist, whose chi-focusing abilities allow for powerful punches and attacks. This is further supported by the Fallout 4 version carrying the description,

Eisenfaust Puño de Hierro Poing de fer Стальной кулак Сталевий кулак 铁拳