Demon

Demons are a class of creature; many are characterized by a mix of human- and beast-like features, often in hellish black or red colours. (Abyssal demons, however, look quite different.)

Demons usually come from other realms, and most if not all are servants of Zamorak. They are generally considered to be fairly strong, except for imps, and have low defence strengths. The ability to slay stronger and stronger demons is often a personal landmark for many players. Demons are especially weak towards magic but not so weak towards melee attacks. The magical swords Silverlight and Darklight are enchanted to be especially effective against demons.

Types of Demon
The following monsters are demons. There are also several demonic monsters in quests:
 * Impling
 * Impling defender
 * Imp
 * Revenant imp
 * Icefiend
 * Pyrefiend
 * Bloodveld
 * Lesser demon
 * Greater demon
 * Black demon
 * Abyssal demon
 * Nechryael
 * Death spawn
 * Imp Champion
 * Lesser Demon Champion
 * K'ril Tsutsaroth
 * Balfrug Kreeyath
 * Zak'ln Gritch
 * Tstanon Karlak
 * Revenant demon
 * Tormented Demon
 * Hellhound (also part dog, but does not count as a dog on Slayer tasks)
 * Delrith
 * Nezikchened
 * Jungle Demon
 * Chronozon
 * Agrith-Naar
 * Othanian
 * Holthion
 * Doomion
 * Tormented Demon
 * Ice demon

Demons in Construction

 * There is a demon butler named Alathazdrar, who can be hired as a servant for a player-owned house at level 50 Construction for 10,000 coins.
 * Players with level 75 Construction may purchase a level 82 greater demon to guard the Treasure Room of a Player-owned house.

Demons that cannot be attacked

 * Implings and Impling defenders in the Impetuous Impulses Minigame
 * Mazchna and Achtryn, demonic Slayer masters.
 * Sergeant Damien, demonic trainer in the Drill Demon Random event.
 * The legendary but deceased Thammaron was an Elder-Demon.
 * Alathazdrar, the demon butler.
 * Hellrats, also part rat.
 * Hellcats, also part cat.

Other

 * Slayer Masters sometimes mention a Bloodveld as a "strange, demonic creature" or a "half-ton demon". However, bloodvelds drop bones when killed, whereas all or almost all other demons drop ashes. This calls into question whether bloodvelds are truly demonic. It has, however, been confirmed that magical swords Silverlight and Darklight have their special effects when fighting bloodvelds. In Portuguese, bloodvelds are called like "Demônio do Sangue", at english "Demon of Blood" or simply bloodveld.
 * Slayer masters describe hellhounds as 'a cross between dogs and demons'. Hellhounds drop bones when killed. It is confirmed that hellhounds are IMMUNE to Darklight and Silverlight effects.

Trivia

 * With 11 different bosses, Demons are one of the most common, if not the most common, race(s) to be quest bosses.
 * According to Evil Dave, Hellrats are demons and are the lowest form of demon, weaker even than imps. Players cannot kill hellrats, but pet cats can.
 * Reldo in Postbag from the Hedge reveals that all demons have true names, however, they do not reveal their true name because "names have powers". Demons that reveals their true names are those that are so powerful that the name cannot bound them anymore. K'ril Tsutsaroth is an example.