Morlu

"The Morlu were once men, great warriors of old. But each of them had darkness within his soul, and Mephisto, the Lord of Hatred, used this flaw to trick them into his service. Mephisto's fury slowly burned away their mortal forms, leaving them fiery apparitions who know no pain, fear, or doubt."

- Deckard Cain

The Morlu are reanimated, frenzied warriors fueled with an unholy bloodlust. Once used as footsoldiers in the Sin War, they have also been sighted in recent times.

Lore
"The morlu were more than just fanatical; they lived and breathed the desire of the Lord of Hatred. They did not sleep, anymore; they did not eat. All the morlu did was fight." Morlu are ram-masked and revel in bloodshed, their bloodthirstiness rivaling that of demons. They possess the ability to communicate through verbal speech and have a sense of smell capable of detecting blood. The morlu under Mephisto were difficult to slay, due to the fact that they were animated warriors. Slain morlu continued to rise, even when pierced by arrows or other weaponry. However, once their heads were removed, the morlu's 'life-force' started to wane (decapitated morlu still remained animated for a short time in which they had to recover their heads, lest they collapse). Also, undead banishing spells have a devastating effect. When the Necromancer Mendeln unleashed his magic against the morlu, they were drained of their 'life force,' preventing further resurrection.

History
The original Morlu were once human warriors. All great men, but all with darkness within their souls. Mephisto used this flaw to trick them into his service, turning them into the Morlu. The term "morlu" was coined by Lucion, a "word of power" that harkened to the magic of Mephisto. They formed a special reserve of heavy infantry in the service of Lucion and the Triune. When not called upon, they resided in an underground cave hidden beneath the main Temple of the Triune, constantly battling one another. Each morlu fought for itself&mdash;one might fight with another for a time, but inevitably, the two would turn on each other eventually. They used Living Flame against one another to test their resolve. However, when given an assignment by Lucion, they could work together cohesively. Additionally, some morlu disguised as Peace Warders were used within the temple itself.

Whenever a morlu fell in battle, it was resurrected by a demonic artifact known only as the Kiss of Mephisto. Every morlu in Mephisto's service had died at least a dozen times, thus making them experienced and battle-hardened brutes.

The morlu came into contact with the nephalem Uldyssian and his Edyrem followers during the Sin War. They were defeated however.

Thousands of years later, morlu in the service of Diablo were seen in his assault on the High Heavens. These Morlu were seen as both warriors and magic users. When defeated, they momentarily became frozen as a statue of ash and soot. If not destroyed while in this state, they would regenerate and fight anew.

In-game
Morlu appear in Act IV of Diablo III. They are divided into casters and berserkers, which focus on spellcasting and damage dealing respectively. They are classified as demons rather than undead for gameplay purposes.

Their most unique ability is that upon reaching 5% Life, they turn into immobile statues of ash, and remove all Damage Over Time effects. Unless killed in 10 seconds after that, they will be healed to 1-100% of maximum health.

Trivia

 * Due to an animation glitch, if a Morlu is killed outright (for example, by spawning a Rift Guardian in a Greater Rift), they will turn into an ashen statue and will not crumble, remaining as a monument permanently.

Known Morlu

 * Damos
 * Ember
 * Kao'Ahn, Morlu High Lord
 * Malfeas the Abhorrent, Hand of Corruption
 * Oah'Tash
 * Rhau'Kye, the Eye of Flame
 * Rime
 * Sao’Thall, Embodiment of Hatred
 * Xah'Rith, the Keywarden