The Chainsword is a fuck-awesome melee weapon, heavily used by Imperial forces, although variants are fielded by the Eldar, Orks, and Chaos Space Marines. Apparently in the 41st Millennium, chainsaws have been re-purposed for hacking down things/aliens/people instead of simply harvesting lumber. As its name implies, the chainsword is a bladed weapon with a rotating chainsaw blade in-between, that's powered by a motor mounted on the hilt and activated with a trigger on the grip. Of course, the sheer manliness in this weapon makes it pretty damn heavy, so it's actually really fucking awesome. But since almost all the users of it have some combination of power armor, bionics, or natural strength to swing them around, the weight is a lot less of an issue.
Although the chainsword is issued to virtually all forces of the Imperium, it is most famous with the Spehss mahreens who widely use the chainsword as the primary weapon of their assault troops and veteran soldiers, although the standard chainsword has the same rules as any other close-combat weapon. Which is dumb, considering most of the fluff describes it as cutting through armour with ease, even Terminator armour, with some additional effort. Because a giant chainsaw does as much damage as a combat knife.
The Chainsword also has several variants that have been developed by both the Imperium of Man and Xenos. Here are some examples:
An oversized chainsword used by the Ecclesiarchy's priests and by the Sisters Repentia of the Sisters of Battle (as well as Chapter Master Gabriel 'IN THE BALLS' Seth). Most recently however, Eviscerators have found their way into the hand of 7E assault marine sergeants, because meltabombs just weren't enough. The Eviscerator is twice the size of a regular chainsword and so heavy that a normal soldier will need to wield it using both hands. The Eviscerator might also incorporate an exterminator, a portable flame unit that will not only help it breach armor, but also scare the fuck out of any normal man upon seeing a whacked up priest/nun swinging a fucking huge flaming sword-chainsaw. The Eviscerator is also extra effective against armored units. In some works the Eviscerator is described as having a disruptor field weaker than those of energy weapons, which still helps carving through ceramite.
An Eldar variant of the Chainsword fielded by the Striking Scorpions. It's like the Imperial Chainsword but incorporates advanced equipment that increases the wielder's strength and incorporates a sleeker, less bulky design. There's been fluff that suggests they are actually a lot more advanced than Imperial chainswords, consisting of a heavily serrated 41st millennium mono-molecular blade which doesn't whirl around most of the time. Rather, upon hitting an opponent, and the blade gets stuck in their body/armor, THAT's when it goes all chainsaw, ripping armor and people apart and ensuring that the blade doesn't ever get stuck in someone; it'll either go through them or at least rip whatever it's stuck in enough to be pulled out.
Exarchs can use two variations of the Scorpion Chainsword: the Biting Blade (a massive two-handed weapon whose effectiveness increases as a target is hit), and the Chainsabres (two one-handed chain weapons that can land a truly staggering amount of blows on a target).
Yes, Warhammer has chainsaw axes, as insane it sounds. The custom weapon of Khornate champions, the Chainaxe was a fairly common weapon among Imperial troops pre-heresy. It's basically a huge axe with a powerful chainsaw as a blade. Pre-heresy it was practically standard issue among the World Eaters. The sheer weight of the axe and the fact that most Khorne Chaos Marine champions are super strong and completely fucking nuts ensures these will tear through most infantry armor. It's wielded by non-Khornate Chaos Marines as well, due to the greater damage it inflicts, but mostly because of the showers of gore they call "wounds" - represented in 40k rules by being AP4, a straight upgrade from a regular chainsword and the woe of anyone not wearing power armour. Among Imperial forces, a chain-axe is most likely to be seen in the hands of a Space Wolf or a Raven Guard - the former due to the fact that they just don't give a flying fuck that it might associate them with Chaos, and the latter due to the fact that they mostly have older equipment due to infrequent resupplies. They are also very common among Flesh Tearers because they basically already are a Khornate cult.
The Chainglaive is an evolution of the Chainaxe, giving it a longer blade and haft allowing for wide, sweeping strikes capable of rending power armour without much trouble. It's used extensively by Vanguard Marines and Chaos close-combat specialists. An ancient design by modern standards, it's by no means common, and sees use primarily with the traitor legions due to this (particularly with the Night Lords, who had always favored its use).
Seen wielded by the Spyrer Matriarchs, this variant of the chainglaive mounts the blade at a horizontal angle to the tip of the shaft.
Chainaxe not insane enough for you? Black Crusade introduces the chainhammer, a massive maul outfitted with multiple rows of spinning metal teeth on the club-like head, which rip apart flesh pulped by the brutal impact of this insane weapon.
Similarly to the chainglaive, this weapon combines reach with lethality, mounting a chainsaw-bladed length at the end of a long haft, ensuring that jabs and thrusts can tear open flesh with the lightest touch whilst keeping the wielder out of harm's way. According to Tome of Blood, some variants actually sport the sharpened teeth of the bearer's former victims as the cutting edges.
A variant of the chainsword created to allow human heretics to approximate the deadly blows of a Legion chainsword, this variant features a thick, bladed area with chained teeth nearly twice the width of an ordinary chainsword, and powered by a backpack-mounted fuel supply. Its greater tearing strength and weighted nose allow it to deal viciously violent heavy slashing blows. Needless to say, this weapon is heavy - 12 kilograms in weight, complete with power supply - and unbalanced, ie. a very heavy regular chainsaw.
Intended to assist Terminators' not stellar mobility when involved in boarding actions, the Chainfist is a Power Fist that incorporates a powerful chainsaw blade for the purposes of slicing through armored bulkheads. The weapon is commonly used by Terminators both as a CQC weapon and a convenient tool to cut themselves a way through the average Space Hulk's too small doors/walls/ceilings/floors... during boarding actions. Of course, since it can penetrate thick metal with little trouble, it's also often used for ripping open enemy vehicles and bunkers.
The reason it's so effective is simple: the powerfist's energy field also encompasses the chainblade. That's right, the chainfist effectively marries a chainsword and power fist. Remember how a regular power sword cuts most stuff like a hot knife through butter? Now bring a chainsaw with hot knives for teeth into this butter world, wear it like a glove and that's how a chainfist feels. That's just plain scary. If anything, it's like hitting a target with a power sword at 40 strikes per second, so that the powerfield weakens the target and then the teeth hack it away. The alternative is having a static piece of metal that is still cutting, but just not as efficiently.
The easiest way to use a chainfist in combat is to wield it like a Tonfa. As its mounted just under the left wrist parallel to the arm.
The Chain Choppa is the Ork version of the chainsword. The weapon is a handheld chainsaw (though it sometimes takes the form of a sword or axe) used for almost anything. Really, you name it. In a pinch it can stand in for anything ranging from a weapon to a household tool. Regular garden variety Ork Boyz rarely have these weapons, while richer Orks like the Warboss or a Nob might have it because it's killy and flash. Many are simply war trophies picked up from loyalist and traitor Space Marines.
The last word in Chain Weaponry, the Reaper Chainsword is the main weapon of most models of Imperial Knight. Originally designed as a Logging device for feudal colonists, it also works incredibly well as a massive melee weapon, capable of carving open a Super-Heavy Tank with a single blow.
Storm's Teeth - A giant two handed chainsword used by Rogal Dorn himself. It was so large that only a primarch could use it, and it was said to be Dorns favored weapon and is what he used against
Alpharius some random Legionary.
Frost fang - An ancient chainsword used by Ragnar Blackmane. The techniques used to make it were kept a secret by Fergus Forgrim to his deathbed so no one knows how it was made, because it's not like that could have been important or helpful later, right?
Gorefather and Gorechild -
THE BEST WEAPONS IN THE WHOLE OF 40K HERESY. Two chainaxes used by Angron during the Great Crusade and Horus Heresy. The teeth of these weapons came from a MOTHERFUCKING MICA-DRAGON, and are lubricated by BLOOD (these weapons are so metal the bring envy to the Iron Hands and Iron warriors). Gorechild is currently being used by that Swell guy, and Gorefather is no where to be seen, but it might show up again.
Teeth of Terra - Origin unknown, and with a tendency to show up in possession of many different chapters and disappear just as quickly, the Teeth of Terra is an ancient chain sword with obsidian teeth. It strikes hard and deep and allows the bearer to swing in huge, sweeping arcs.
|Weapons of the Eldar|
|Sidearms:||Shuriken Pistol - Fusion Pistol - Neural Shredder - Neuro-Disruptor|
|Basic Weapons:|| Avenger Shuriken Catapult - Death Spinner - Eldar Flamer - Fusion Gun |
Lasblaster - Laser Lance - Prism Rifle - Ranger Long Rifle - Reaper Launcher
Shuriken Catapult - Swooping Hawk Grenade Pack
|Exarch Weapons:|| Dragon's Breath Flamer - Fire Pike - Hawk's Talon - Prism Blaster |
Spinneret Rifle - Star Lance - Sunrifle - Tempest Launcher
|Warp Weapons:||D-Cannon - D-Scythe - Wraithcannon|
|Heavy Weapons:|| Bright Lance - Eldar Missile Launcher - Pack Grenade Launcher - Scatter Laser |
Shadow Weaver - Shuriken Cannon - Starcannon - Suncannon - Vibro Cannon
|Vehicle Weapons:||Doomweaver - Phoenix Missile Launcher - Prism Cannon - Pulse Laser|
|Super Heavy Weapons:||Psychic Lance - Pulsar - Revenant Missile Launcher - Sonic Lance|
|Melee Weapons:|| Diresword - Eldar Power Sword - Executioner - Ghostglaive - Mirrorsword |
Scorpion Chainsword - Scorpion's Claw - Singing Spear - Witchblade