Th is strongly recommended you are of a high combat level (105+), because revenants can easily overwhelm and kill even level 100’s in a few seconds without the proper equipment. Lower levels can attempt to kill the revenants, but they must be wary of other revenants and players. The walls around the room and the ruins will be your only defence from a relentless onslaught of attacks. If meleeing, a good luring tactic is to cast a weak spell or fire an arrow and then hide behind a wall, this will draw the revenant near you without attracting the attention of any others. After it is close, you can melee it without being piled by other revenants. It is advised to bring Jennica’s ring (for better drops) and a forinthry bracelet (to make the revenants un-aggressive). Make sure that, if using a forinthry brace, you use the repel option as soon as you approach the revenant section. This will activate the special; revenants will hit 0’s only for a minute and be un-aggressive for an hour. This timer only runs when inside the dungeon and is paused if you leave the dungeon by any means (including death). The forinthry bracelet’s effect DOES NOT work in a F2P world. You can also use the single-way ability so that revenants can not pile you.
Ankous can be found in the north-western section of the dungeon. As this is level ~30 Wilderness, it is advised to go to the Sepulchre of Death in the Stronghold of Security, where there are also numerous ankous. Crumble Undead and stab attacks work very well against Ankous. Safespots for rangers and halberdiers can be found at the eastern rift, where ankous are easily trapped. However, they are aggressive and you will likely be attacked by ankous while safespotting another one. They frequently drop high amounts of blood and death runes, as well as level 3 clue scrolls. There are 8 spawns of Ankous there, and it is not recommended to kill them there as it is a multi-way combat area, and PKers can arrive and loot your Blood and Death runes for their Ancient Magicks.
Lesser demons can be found in the western/middle section, east of the ankous and west of the hellhounds. It is not recommended to fight them here, as there are safer spots, like Karamja Volcano. It is advised to bring an Accursed urn (or Infernal urn) to collect the ashes for extra Prayer experience. There is also a rift in the middle to trap the demons, but it is a multi-combat area. They can be acessed by turning left at the Hellhounds, or if coming from the level 31 area, go left and a path will split up. Take the left one to go to the Lesser demons.