Avernus	Dis	Minauros	Phlegethos	Stygia
Malbolge	Maladomini	Caina	Nessus	-
Hell	-	-	-	Manual of the Planes

Dis, the second layer of Hell,
is dominated by the city of the same name.
This massive edifice rises from the low hills && stagnant rivers (black && poisonous) to several miles in height and hundreds of miles across.
Several barriers from Avernus lead to the upper levels of this fell city,
though none lead into the stone && lead inner sanctum of Dis himself,
who rules this realm.
Beyond the walls of the Iron City,
the land is flat and barren,
rising some thousands of miles away into low,
rolling hills.
All the lands are capped by a heavily overcast sky of dull greens lit by flickers of lightning. <link: WSG, lightning>

An excellent example of this is Druaga, a lesser Power of the
Babylonian mythos, who is titled (perhaps self-titled) Ruler of the
Devil World. Druaga has a {realm} in The Second Hell,
far from the hills that surround Dis's flat plain. Both he and Dispater
are aware of each other and tolerate each other's presence in
their layer of Hell. Neither interferes with the workings of the other.
Dispater may provide the devils that Druaga sends forth, but
the full nature of this relationship is unrevealed.

Frequency of Devils on Dis (The 2nd Hell)

Ruler = Dispater	Abishai = C	Arch = VVR	Barbed = U	Bearded = R	Bone = 0	Erinyes = C	Horned = VR
Ice = 0	Nupperibo = C	Fiend = VR <alt>	Spined = C	Styx = 0	Achaierai = C	Barghest = VR	Daemon = VR
Hell Cat = U	Hell Hound = U	Hoardling = U	Imp = C	Lemure = R	Mephit = C	Nightmare = R	Rakshasa = C
Stench Kow = C	->	->	->	->	->	->	<>

-

Tiamat	Dispater (Arch-devil)	Geryon (Arch-devil)	Mammon (Arch-devil)	Asmodeus (Arch-devil)
Belial (Arch-devil)	Mephistopheles (Arch-devil)	Baalzebul (Arch-devil)	Moloch (Arch-devil)	-

(Notes)
 

Die Roll	Frequency
2	Very rare
3	Very rare
4	Very rare or rare
5	Rare
6	Rare
7	Uncommon*
8	Uncommon*
9	Common**
10	Common**
11	Common**
12	Common**
13	Common**
14	Uncommon*
15	Uncommon*
16	Rare
17	Rare
18	Very rare or rare
19	Very rare
20	Very rare

* Alternately; choice of two very rare creatures.
** Alternately; choice of two rare creatures.

<Gnarley Bones did an excellent random encounter table for Dis over at at DF. Be sure to include it!>