Greater demons are demonic creatures commonly assigned as a slayer task by Krystilia, Chaeldar, Konar, Nieve/Steve, and Duradel/Kuradel. They are good slayer tasks as they give great XP rates, are cannonable and AFK.
There are 11 locations where you can find Greater Demons, and here are the best ones for killing them:
Karuulm slayer Dungeon: There are 9 level 92 Greater demon spawns in this location. The fastest way here is with fairy ring CIR or with the skills necklace to the farming guild, southwest of Mount Karuulm.
Greater demons in the Karuulm slayer dungeon are found in the middle level. The path to this level is shown below.
Catacombs of Kourend: There are a total of 10 level 100, 101, and 113 Greater Demons in this location.The fastest way to get here is through the portal chamber or nexus in a POH attuned to Kourend Castle. Alternatively, players can use Hosidius's page in the Kharedst’s memoirs, or fairy ring CIS.
Chasm of fire: This is a slayer task-only area which contains 11 level 92 Greater Demons. The dungeon is located in the northwest corner of Shayzien. The fastest way here is with fairy ring DJR which takes the player southeast of the Chasm.
Head slot: Slayer helm(i)
Neck slot: Amulet of rancour
Cape slot: Infernal cape
Body slot: Torva platebody
Leg slot: Torva platelegs
Weapon slot: Emberlight
Shield slot: Avernic defender
Ammo slot: Rada’s blessing 4
Glove slot: Ferocious gloves
Boot slot: Primordial boots
Ring slot: Ultor ring
Head slot: Slayer helm(i)
Neck slot: Amulet of fury
Cape slot: Fire cape
Body slot: Proselyte hauberk
Leg slot: Proselyte cuisse
Weapon slot: Arclight
Shield slot: Dragon defender
Ammo slot: Rada’s blessing 3
Glove slot: Barrows gloves
Boot slot: Dragon boots
Ring slot: Berserker ring (i)
Head slot: Slayer helm(i)
Neck slot: Necklace of anguish
Cape slot: Dizana’s quiver
Body slot: Masori body (f)
Leg slot: Masori chaps (f)
Weapon slot: Toxic blowpipe
Ammo slot: Rada’s blessing 4
Glove slot: Zaryte vambraces
Boot slot: Pegasian boot
Ring slot: Archer's ring (i)
Head slot: Slayer helm(i)
Neck slot: Amulet of Fury
Cape slot: Ava’s accumulator
Body slot: Saradomin d’hide body
Leg slot: Saradomin chaps
Weapon slot: Toxic blowpipe
Ammo slot: Rada’s blessing 3
Glove slot: Barrows gloves
Boot slot: Saradomin d’hide boots
Ring slot: Archer's ring (i)
Greater Demons attack with melee with a max hit of 10. Protect from melee will provide complete protection from their attacks.
The Catacombs of Kourend is the best location to kill Greater demons since you can complete the task while being AFK. Although cannons are not allowed there, it is a multi-combat zone, so multiple Greater demons will attack you at once, so you don’t need to do anything as long as auto-retaliate is turned on. When they become unaggressive, walk a couple of tiles away from the area and return to reset their aggression.
If you want to use a cannon, then kill the Greater Demons at the Chasm of Fire or Karuulm Slayer Dungeon, where a cannon can be used. Setup the Cannon at the middle of their spawn locations, shown above to get the best XP rates.
After entering the Mount Karaluum, enter the lift north and run to the spot shown above. You can use ranged and your cannon to attack the Greater Demons while at this safespot. Use the minimap to better locate this spot.
Always
1 Vile ashes
Weapons and armour
1 Steel 2h sword (1/32), 1 Steel axe (1/42.67), 1 Steel battleaxe (1/42.67), 1 Mithril kiteshield (1/128), 1 Adamant platelegs (1/128), 1 Rune full helm (1/128)
Runes
75 Fire rune (1/16), 15 Chaos rune (1/42.67), 5 Death rune (1/42.67), 37 Fire rune (1/128)
Coins
132 Coins (1/3.2), 44 Coins (1/4.44), 220 Coins (1/12.8), 11 Coins (1/18.29), 460 Coins (1/128)
Other
1 Tuna (1/42.67), Nothing (1/64), 1 Gold bar (1/64), 1 Thread (1/128)
Gems (5/128 chance of rolling)
1 Uncut sapphire (1/102.4; 1/54), 1 Uncut emerald (1/204.8; 1/109), 1 Uncut ruby (1/409.6; 1/218), 1 Uncut diamond (1/1,638; 1/832), 1 Chaos talisman (m) (1/1,092; 1/555), 1 Nature talisman (m) (1/1,092; 1/555), 1 Loop half of key (m) (1/3,277; 1/1,646), 1 Tooth half of key (m) (1/3,277; 1/1,646), 5 Rune javelin (1/3,277; 1/1,646), 1 Rune spear (m) (1/52,429; 1/26,244), 1 Shield left half (m) (1/104,858; 1/52,488), 1 Dragon spear (m) (1/139,810; 1/82,304)
Tertiary
1 Looting bag (1/3), 1 Ensouled demon head (1/40), 1 Brimstone key (1/112–1/64), 1 Clue scroll (hard) (1/128; 1/64)