The Doom 64 Unmaker, on MAP28: The Absolution
The Doom 64 Unmaker being used against an Arachnotron, on MAP23: Unholy Temple
- "What the !@#%* is this!"
- ― Doom 64 when collecting the weapon.
The Unmaker (aka Unmaykr or Laser) is a weapon found in Doom 64, Doom Eternal and Mighty Doom.
Background[]
Doom 64[]
The Unmaker's appearance in Doom 64 has a demonic theme, though the relation between the weapon and the demons remains a mystery. Once fully upgraded, it is arguably considered the most powerful weapon in the series, able to rapidly fire a spread of lasers that cause high amounts of damage. The Unmaker can be upgraded by playing through the secret maps and acquiring the Demon Keys to upgrade it's firepower. The weapon is especially effective against the Mother Demon on Map 28: The Absolution and the "Resurrector" on Map 39: Final Judgement once all three keys are obtained.
Doom Eternal[]
The Unmaker reappears in Doom Eternal as the Unmaykr. It's built with Maykr technology, inspired by Sentinel weaponry and refined by the the Maykrs' divine intellect. In contrast to its Doom 64 design, this weapon has a distinctly "angelic" appearance like that of the Maykrs. Its fire rate and spread is similar to the Doom 64 incarnation with all Demon Keys unlocked, firing three projectiles per shot with a high rate of fire. The Unmakyr is unlocked in the Fortress of Doom by obtaining all six Empyrean Keys.
Mighty Doom[]
The Eternal version of Unmaykr is one of four equippable Ultimate weapons in Mighty Doom. Once it is charged up after killing many demons, the player can manually fire the Unmaykr to unleash three rapid-fire streams of Argent energy in a spread-shot formation that inflict plasma 
damage, color-coded purple. At the beginning of a run, provided that the player obtained the Starting Ability Mastery, the player may have a chance to acquire its passive ability 
"Maykd to Last", which increases the player's defense (damage resistance) by 20% for that run.
For these reasons, the Unmaykr is the least accurate and most defensive of the four Ultimates, due to its inaccurate spread-shot attack making it more effective at close quarters than from a distance in boss battles, the defensive nature of its passive ability, and the significant time taken to exhaust its entire ammunition providing a significant period of invincibility while the Slayer's movement can still be controlled by the player while using it.
Behind the scenes[]
It was originally a weapon from the Doom Bible which was originally intended to be in Doom, but was subsequently removed. However, it later appeared in Doom 64.
According to the Doom Bible, the Unmaker was intended to be a demon-tech weapon made of demon bones. The Dark Claw and Unmaker feed on human souls, so killing possessed humans or hellslaves allows the weapons to feed.[1] This idea was later used for the Soul Cube in Doom 3 and the Artifact from Resurrection of Evil.