Sulfur City is a location that was shown from the animated series, Angel's Friends and the film, Angel's Friends: Between Dream and Reality. It was also considered Hell itself where all the devilish and evil creatures live without any rules.
Sulfur City is ruled is by the Low Spheres, whose faces are never shown and their voices are the only thing that are heard through the animated series. The city of devils, unlike the city of angels, isn't that much like an Earthly city, and it's filled with volcanoes and seas of lava (magma). However like a normal city, it contains shops, bars, discos, transfigured however possesses a devilish look and is stuck to the ground, among dust and sulfur smoke. At the service of the Low Spheres are the Malebolge and the Diabolic Army, plus Temptel's Diabolic war guards.
The Low Spheres Tower
The Low Spheres Tower as its names says, is the tower where are located the Low Spheres, the place where the Devil teachers, including Temptel go in order to report to the Low Spheres how things are going in the students' stage. Unlike the High Spheres Tower in Angie Town that does appear once in the animated series, it is never shown from the outside and the only room from that tower that is shown is the Low Sphere Room.
From the inside, the tower has got a round shaped floor and walls made of rocks, at the middle of the room the floor is broken and that hole is filled with real lava that however does not burn any of the rocks of the room. In the center of the lava circle is a floating rock which is the place where the teachers go when they are talking with the Low Spheres.
The room is sustained by long and large, royal blue and golden Egyptian architectural columns which are set at the doors of the Low Spheres. The number of doors (purple with two golden stars in the center) of the leaders of the Devils are, like the High Spheres', five.
The Mortal Portal
The Mortal Portal is the portal, equivalent to the Angels' Big Door, that every year thousands of devils must cross in order to go down to Earth. It is a big reddish-brown rock structure, build in the middle of many other rocks and inside the structure is a grey metal door.
The Mortal Portal is guarded by a Guardian Devil, he holds in his hand a spear that he uses to keep intruders from entering the city. Unlike in Angie Town, in order to enter the city the devils. The Guardian of the Mortal Portal must say a password: Red Horn. That was revealed on the second part of the episode, Mission Impossible, when Raf and her friends that were disguised as devils, try to enter in the city and remember that Sulfus told them the password.
The Guardian however is somehow deaf and either real or false devils can get into serious trouble if he hears the wrong password.