Iron Fist

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

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

Fallout 76
Iron Fist is a perk in the Nuclear Winter battle royale mode.
 * Nuclear Winter

Behind the scenes
The perk is may be a reference 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,

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.

Eisenfaust Puño de Hierro Poing de Fer Стальной кулак Сталевий кулак