Power Fist

A Powerfist is a weapon in the Warhammer 40,000 universe. Around since the first incarnation of Warhammer 40,000, there have been several models and parts of models that have a power fist. It is essentially an oversized, armoured gauntlet that generates an energy field around it that disrupts any matter it touches. It is a favoured close combat weapon for the Imperium, as well as the forces of Chaos (particularly the Chaos Space Marines).

In the table-top game, it has the effect of doubling the user's strength while ignoring armour saves, making it devastating against infantry and pretty effective against enemy armour. It has the disadvantage of forcing the user to strike last, making them vulnerable to attack from others before they get a chance to strike. A popular choice for weapons that go with a power fist are the combat shield and bolt pistol or just a storm shield.

Variants
From time to time, the Terminator's (and occasionally, Assault Space Marines and Space Marine Heroes') Powerfist has also been known as Power Gloves, especially in the Space Hulk PC game. However, the Dreadnought's close combat weapon has always been known exclusively as the Powerfist, and it is more powerful than its infantry equivalent since it does not force the dreadnaught to strike last and because it is more effective against heavily armoured vehicles. The Space Wolves Venerable Dreadnought (Bjorn the Fell-Handed) has a lightning claw instead of a powerfist, but currently it counts as a regular dreadnought powerfist for gaming purposes.

One variant is the Lightning Claw. It consists of a powered gauntlet, fitted with three or four blades. A matter-disrupting energy field is projected around the blades, allowing them to cut through armour and flesh with minimal effort. Lightning claws are almost invariably worn as a pair. They are more specialized than powerfists, being extremely effective against enemy troops but having little impact on vehicles.

Another variant is the Chainfist, similar to a Powerfist, but with a reduced, powered chainsaw blade attached. It was originally intended for breaching bulkheads on starships and hulks but it is equally adept at tearing up vehicles. It is treated as a power fist against infantry, but its purpose is tearing up armour, where it excels.

Most Terminators are equipped with a Storm Bolter and Powerfist. Occasionally, the Chainfist will substitute for a Powerfist in case the situation calls for it.

Other Races
The Orks use a variant known as a Power Klaw, which is a large claw with three bladed fingers. The wielders of such weapons can easily rip apart armour of any kind with them.

The Eldar Striking Scorpion Exarchs employ a variant called Scorpion's Claw, which integrates a shuriken catapult and a Powerfist, and is shaped like a hand sized claw of a scorpion.

Lightning Claw
A Lightning Claw is a specialized type of power weapon, based on the design of the Powerfist.

A Lightning Claw consists of a powered gauntlet, fitted with three or four blades. A matter-disrupting energy field is projected around the blades, allowing them to cut through armour and flesh with minimal effort. Lightning Claws are almost invariably worn as a pair.

Lightning Claws are most commonly used by the Space Marine Chapters - by Assault Marines, Terminators and some officers, for example, Captain Kayvan Shrike of the Raven Guard and his retinue, Shrikes Wing - and also has been used by the Chaos Space Marine Legions, Abaddon's Talon of Horus being an example. General Sturnn, from the Winter Assault expansion pack for the Warhammer 40,000: Dawn of War video game, also wears a pair of Lightning Claws, although balance issues and game mechanics prevent the matter-disrupting properties of table top Lightning Claws being applied to them.

In the tabletop game, Lightning Claws count as a Power Weapon and enable the user to re-roll failed 'to wound' rolls. If worn as a pair, they allow the user to make an additional attack. Because of this most players will pay the extra point cost to 'Master-Craft' their Lightning Claws to ensure hits and wounds. Lighting Claws are most often mounted on Terminators (to ensure they actually get into combat before getting killed) or on jump pack-equipped heroes (as their superior stats will complement the Claws).

The Space Wolves Venerable Dreadnought (Bjorn the Fell-Handed) has a Lightning Claw instead of a Powerfist, but currently it counts as a regular Dreadnought Powerfist for gaming purposes.