|“||I, Mortamor, am the lord and master of every living creature! You will bow before my supreme power!||„|
Despite having multiple forms, they often resemble red demons. His first form is an old man with a long beard and a prominent forehead that wears purple robes, baggy yellow pants and uses two yellow spheres to attack and cast spells. His second form is a winged burly red demon with massive defense and strength. Finally, he will cast away that last body and break apart a dimensional wall to come out as his strongest form: A giant bearded demon-like head with purple hair circling his non-visible neck and a pair of disembodied claws that, judging by its entrance, could have his body anchored in another dimension.
|“||Dreams are a wonderful thing, yes? Dreams give you hope, and hope gives you the power to live. But sometimes, dreams can be making you greedy... That creature... He was consumed by his dreams - by his greed.||„|
|~ Madame Luca about Mortamor|
Mortamor is known by a few people who know him as the Archfiend, the supreme enemy of the Real and Dream Worlds and the master of the Dread Realm, a dimension o his own, set apart from the said worlds. It's not specified how he or his realm came to be but, according to some NPC dialogue, it was a monster that became too greedy with power and fed on the woes, greed and negative emotions of creatures. There are some unfortunate souls that ended in his world one way or another and are suffering by his schemes and tortured by its demon minions. The sages Benjamin and Isaac who represent probably the biggest threat to him, are among these people. Peggy Sue cannot transform into Pegasus while in this world.
- Mortamor's final form appears as a legacy boss in Dragon Quest IX if its map is obtained.
- His final form appears as an X Rank Unknown Family synthesizable monster in Dragon Quest Monsters Joker 2, requiring Nimzo and Estark to be made.
- He's one of Nokturnus' finest warriors in Dragon Quest Battle Road Victory and the final boss of the Dragon Quest VI story arc. He fights in his second form.
- Mortamor is the first final boss in the series composed of three parts: two claws and its head. Also, all of them have to be defeated to win as both claws can revive its head, though the right claw is less likely to do so.
- According to its description in Dragon Quest IX, he "asseses opponent's strength, then assumes a disguise to suit the situation, nobody knows how he really looks like" so it's possible that even his final form is not his true one. Although he posseses a yellow sphere that can multiply that may be related, or may even be, his true self.
- After the player defeats Mortamor, the game ends. However, there is a secret ending that can be viewed by defeating the game's secret final boss in less than 20 turns, which involves him toying with and overkilling Mortamor.