E4M5: Great Stair (Heretic)

E4M5: Great Stair is the fifth level in The Ossuary episode of Heretic Shadow of the Serpent Riders.

Essentials
Beginning

You start in a circle that seemingly has no way out. (A) The southern wall of the central structure (B) differs from the rest as it is bordered by small metal panels. Press the wall between the small panels to find a hidden chamber inside the central structure. When you are about to take the Ethereal Crossbow there, three sections will descend in the chamber, each having a fire gargoyle. In addition, a few weredragons will become released in the corners of the circle outside (on the three highest skill levels). When you step in any of the gargoyle areas, a door will open on the southern side of the circle. Enter the zone beyond it.

You will arrive at a hall that consists of three different levels and is populated by weredragons. (C) Right after entering, turn left and have the Quiver of Ethereal Arrows in the corner in front of you. The two higher levels of the hall will be visited later in the map. For now, you need to press the switch nearby. It will open a door on the eastern side of the aforementioned circle and give access to a new area. (D) Before leaving, you can visit the staircase to the west of the switch and confront the ophidian at its other end. The monster guards a Silver Shield.

Two long passages begin at the new area. (D) Destroy the fire gargoyles and hit the switch next to the banners. Stairs will form in the southern passage. Notice that the weredragons on the ledge (E) are able to approach you once the staircase is complete. You can try to use the brown columns as shields from the fireballs that are shot towards you from both directions. (E & O) Clear the opposition of the southern ledge and start looking for the missing key.

Yellow key

A short staircase connects the ledge (E) and the middle area of the three-level hall. (C) As previously, when you arrive at the hall, you can turn left to grab an item in a corner. This time, there is a Bag of Holding. Beware the existing weredragons of the hall and make your way to its other end, where you can continue on another staircase. On the bottom, you will find a rectangular hall that has a pool of lava in its center. (F) In addition, each corner of the area has a station where a weredragon lurks. Take into account that when an arrangement of five small pillars is located between you and a weredragon, the monster's fireballs cannot reach you. Despite the limited threat, you have to be careful in the room as many ophidians can fire you from the passage behind the eight windows. (N) Furthermore, there is a group of fire gargoyles in the eastern passage next to the unreachable platform that holds the yellow key. (G) If you control the situation, you can acquire the Tome of Power in the northwest weredragon station.

Like in the beginning of the map, you need to find a hidden door to proceed. The door is located at the lava pool that surrounds a gray building. The structure's eastern wall (H) has a bright skull with red eyes. Open the wall to find a room with a teleporter and a Ring of Invincibility. However, before entering the room, you might want to follow the platform by the lava to the other side of the structure as the Gauntlets of the Necromancer are kept there. After stepping on the teleporter, you will reach the top of the key platform. (G) When you leave it, a large area will descend next to your location uncovering three iron liches. (I) At the same time, a doorway opens between the descended area and the circle. (I & A) Destroy or distract the enemies and collect a Crystal Geode, a Torch, a Chaos Device and a varying amount of Quartz Flasks in the room they guarded.

Green key

Return to the yellow door (E) and enter it to find yourself at a fork. Instead of opening the wooden door, go forward and activate the metal lift in front of you. (J1) When you take the Energy Orb on the descended lift, be prepared for an attack by two fire gargoyles above you. When the lift is up, step in the side room of the gargoyles and have the Shadowsphere. Continue by using a similar lift nearby. (J2) As you collect the Dragon Claw, you will soon meet two new fire gargoyles on the top, but there is also a varying amount of weredragons up there. Take the Tome of Power in the side room once you are on level with it and follow the passage until your way is blocked by a stained glass painting. (K)

The passage in front of you has five rooms in a row, each of which is surrounded by a door of which sides are covered by a stained glass painting. When you hit a door with any weapon, it will open permanently, revealing an ophidian and a Timebomb of the Ancients. If you want to play it safe, you can open a door and lure an ophidian away from a position where you could accidentally shoot the next door. While this method is slow, it has the benefit of facing only a single monster at a time. However, if you want to spare time, attack enemies as they become revealed. Keep in mind in any case that there are several ophidians behind the fifth room.

When you have secured the area beyond the five rooms, press the switch at the northern end. (L) It will lower a platform that allows you to reach the green key. (M) Go to the other end of the area where you will find a long staircase. Be careful not to become shot by remaining ophidians. If you turn right at the end of the stairs, you will see a Mystic Urn that stands on the platform you lowered previously. However, the end of the passage (N) has a Hellstaff, the Wings of Wrath and a Pile of Mace Spheres which you might want to have. When you arrive at the items, you may notice an eagle insignia on the northern wall.

If you step in front of the Mystic Urn, the platform will start to rise. If it goes up without you, return to the switch upstairs and press it again. (L) Rise with the platform. Get rid of the guarding ophidian, have the green key (M) and kill the weredragons so that you can exit the ledge you stand on. You are on the highest area of the three-level hall (C) and you should find your way back to the area where you raised the staircase. (D) On your way there, you might face monsters that have left their position. When you arrive at the switch located next to the banners (D), you will notice that a staircase has now formed in the northern passage too. Go to the ledge (O) and press either of the banners on the side. The walls are doors that hide the way to the green door.

Blue key and exit

You are on the bottom of an elongated hall that consists of five levels. Four staircases connect the first level and the second level, three staircases connect the second level and the third level and so on until there is a separate staircase providing the route from the fourth level to the fifth level. Your goal is to reach the latter (P) and press a switch there. It will make the blue key (Q) available near the beginning of the map. There are ten sabreclaws and many fire gargoyles in the hall, so make sure to get rid of them. The top level is guarded by an iron lich on the two easiest skill levels and by a maulotaur on the higher ones. However, you can collect two units of Greater Runes halfway the hall, which is enough of ammo for killing the monster or bringing it near its death. When the coast is clear, go to press the switch. (P)

On the southern side of the green door (O), go down the stairs and turn left for the blue key. (Q) The final challenge is to get back to the top of the stair hall (P) and unlock the blue doors there in order to exit the level. However, when you take the key, the southern sides of the six structures between the staircases (R-W) will open revealing rooms with disciples. In fact, if you shoot at that point, the disciples will already be alerted in the north and they will start to approach you. Thus, if there are no monsters left on the path to the green door, you will be able to get past the disciples before they start to exit the rooms. Alternatively, you can fight the disciples and visit their stations for pickups:


 * R: Enchanted Shield
 * S: Phoenix Rod
 * T: Map Scroll
 * U: Timebombs of the Ancients (not on skills 4-5)
 * V: Timebombs of the Ancients (not on skills 4-5)
 * W: Bag of Holding

On the top (P), open either of the blue doors, beware the fire gargoyles in the room beyond and step on the exit teleporter. (Ω)

Official

 * 1) When you pick up the blue key (Q), you will open many disciple rooms in the north. (R-W) However, that very same trigger will also open the wall with the eagle insignia near the place you got the Hellstaff. (N) Return there to find a new area. (sector 215) A Mystic Urn, a Tome of Power, a Quartz Flask and a unit of Greater Runes can be found inside. When you enter the teleporter, you will end up on the fourth level of the stair hall (X), which allows you to reach the blue doors without facing any opposition.

Non-official

 * 1) In the room with the yellow door (E), the northwest corner has a square-shaped area that is slightly darker than the environment. When you press the banner on the square's northern wall, the area will descend as a lift. The room on the bottom (Y) has a weredragon, a Quartz Flask, an Inferno Orb and a Morph Ovum. Use the teleporter to exit the area.

Firemace
If the Firemace has appeared at the level startup, you will find it from one of five different positions. In order of appearance, they are located
 * in the sole non-official secret. (Y)
 * in the northeast corner of the yellow key hall. (F)
 * in front of the switch that controls the platform of the green key. (L)
 * on the southern side of the green door. (O)
 * in the exit chamber. (Ω)

If the weapon did not appear, the next chance to obtain it is on E4M7.

Current records
The records for the map at the Doom Speed Demo Archive are:

The data was last verified in its entirety on November 29, 2021.

Player spawns
This level contains four spawn points:
 * 1) facing north. (thing 74)
 * 2) facing west. (thing 75)
 * 3) facing north-east. (thing 76)
 * 4) facing south. (thing 77)

Things
This level contains the following numbers of things per skill level: