Directed energy weapons (not to be confused with various exotic energy weapons) are also a common sight in the Imperium. Instead of shooting a solid projectile of some sort at the target, they cause damage by directing some form of energy at the target. The manufacture of energy weapons generally relies on high-tech not readily available to the Imperium – as a result most energy weapons are made by the Adeptus Mechanicus, or by local tech-guilds producing under Mechanicus license (mostly pure lasweapons).

Lasguns: Laser weapons – or lasweapons as they are known – are very common in the Imperium, made under Mechanicus license on thousands of worlds. The ubiquitous lasgun is also made iconic because it is the standard longarm of the Imperial Guard – there are quite literally billions of such weapons floating around the galaxy. Many xenos species also utilize las-weapons. The Eldar, for example, equip their Guardians (and certain Aspect Warriors) with advanced lasguns that fire into the Gamma-ray part of the spectrum (a technological feat only certain ancient Magi can duplicate).

Lasguns are among the most versatile of beam weapons, with a wide range of offensive and defensive applications. All lasguns are solid-state, using a solid crystalline material as the lasing medium. They require no hazardous chemicals and are compact, light, durable, and easy to use.

Laser weapons usually have variable settings; ranging from dazzle lasers that cause temporary blindness, via blinding lasers that cause permanent damage to eyesight or optics, to high-energy lasers that physical burn damage. Many military lasguns will only have the high-energy setting and many such weapons also have a hotshot option that increases output/damage at the expense of firing rate and energy consumption. All state-of-the-art lasweapons are of the variable-spectrum type, with the integrated machine spirit automatically attuning the beam frequency for optimum performance (meaning that lasweapons can operate effectively in vacuum, fog and atmospheric pollution, even underwater). Military lasweapons are sometimes capable of automatic (or pulse-mode) fire. When firing on automatic lasweapons deliver longer and more energetic pulses, but with less beam coherency, leading to somewhat increased damage at the expense of armor penetration (some models can actually fire in pulse mode even in single shot or semi-automatic modes).

Although the lasbeam is invisible the use of a hi-power lasgun will give away the firer's position because of DEW lines (Directed Energy Weapon lines – a very brief visible line caused by the energy release ionizing air molecules and burning atmospheric pollution along its path – reminiscent of a faint and short-lived lighting bolt), thermal blooming (the air around the gun's muzzle will heat dramatically – easy to spot using IR-equipment) and associated sonic shock wave (the sudden increase in pressure and temperature causes a thunder-like sound). Lasweapons are also effectively recoilless, but the powerful thermal/sonic effect on the atmosphere next to the muzzle tends to slightly disrupt aiming, meaning that lasguns are highly accurate but not fully stabilized when used as automatic weapons.

Hellguns: Hellguns (or blasters) are similar to lasguns in that they fire a beam of coherent light at the target. The difference it that hellguns use the las-beam not only to cause burn damage, but to guide a beam of charged particles at the target (so the hellgun is really two guns in one – a lasgun and a charged-particle accelerator).

Hellguns are much more portent than pure las weapons, but sacrifice the low bulk and ease-of-use that characterizes lasguns. Hellguns are also much more difficult and expensive to make, which of course prevents ordinary guard units from employing them – hellguns are usually only carried by Stromtrooper Regiments or other elite formations.

Hellguns come in a variety of shapes and sizes, ranging from hellpistols, via rifles, to heavy heavy support weapons (such as the Oerius Pattern Hellripper Support Weapon). Since hellguns go through a lot of power very quickly they are often attached to an external power source – like an atomic-stack battery (found in most power armors or carried as separate backpack units by Imperial Stromtroopers for example – such batteries contain power to last through most battles). Support weapons are invariably either connected to a heavy-duty capacitator or more frequently runs of a dedicated power generator or siphons power from an external power source (such as a vehicular power plant). Hellpistols are by comparison severely limited – even with less powerful blasts they go through a standard power cell very quickly.

Plasma guns: Plasma guns are another variation of the lasgun that use a powerful laser to turn a hydrogen pellet into a high-temperature plasma state. The plasma is contained and subsequently accelerated and released along the path of the laser beam – or rather along the evacuated tunnel left by the laser beam (otherwise the plasma would immediately scatter.

The plasma guns produced by the Adeptus Mechanicus are incredibly advanced weapons that only they can build and maintain. Capable of variable rapid-pulse/sustained fire these weapons are among the most devastating weapons found in the Imperial arsenal, capable of shredding hordes of armored opponents or bringing down even hardened single targets. Cruder versions crafted by lesser tech-guilds can also be found, but such pieces are invariably bulky and incapable of outputting the same volume of fire (but they are no less deadly). Several xenos races also utilize similar weapons – the Tau deploy powerful and slow-firing plasma-pulse weapons.

Plasma weapons have good ranges and excellent penetration due to their dualistic kinetic/thermal payload. The effect of a sustained plasma blast on flesh is devastating – only bones and deeply charred reside will remain. Even if a plasma gun fails to penetrate armor it can – quite literally – cook the wearer. Plasma weapons are loud and bright – similar to lasweapons, only several magnitudes more intense. Plasma weapons range in size from pistol, via rifles, to support weapons.

Melta guns: Melta (or fusion beam) weapons are a variant of the plasma gun that sacrifices range and rate of fire for pure destructive power. The name of the weapon is evocative – the star-hot temperatures of the plasma beam literally melts through armor and burns the target.

The only faction within the Imperium with the skills required to make these weapons is the Adeptus Mechanicus – they make melta weapons strictly for military use, supplying them to the Imperial Guard and Astartes for use as anti-armor weapons. Inferno pistols (miniature melta weapons) are very rare, but priority units can expect to have access to melta guns if the situation warrants it. The Eldar are known to use melta guns in the anti-armor role.