The Mazoku

The Mazoku are considered as the MAIN enemies of the Slayers. There are 4 Dark Lords under the Lord of Nightmare:
1. Ruby Eye (Shabranigudo)
2. Dark Star (Dogradigudo...if I'm not mistaken...)
3. Chaotic Blue
4. Death Fog

and each Dark Lord are from different Dimentions(Ruby Eye is from Lina's world, maybe Dark Star is from Lost Universe...duh...). Each Dark Lord has 5 servants (the Dark Leaders) and each servant has a general and a priest:
1. Chaos Dragon Garv
:Maryu-ou Garv( Demon Dragon King)
: his general is Rashaat
: his priest is Raltalk
: fought against the dragons in the war 1000 years ago.
: he got killed fighting with the Water Dragon Queen and his soul was reincarnated in a human's body, because of this, he goes against Ruby Eye.

2. Dynast Graushaila
: Ha-ou (Supreme King)
: his general is Shaila (appeared in the novels but was killed)
: has 2 priests, Grau and Grou.
: lives in the North Pole
: smartest and the most EVIL (ruthless) of the Dark Leaders
: takes form of a young man, real form is of a huge black blob-like creature.

3. Hell Master Fibrizo
: Mei-ou (Underworld King)
: the most powerful among the 5 Dark Leaders
: his priest and general were killed during the Kamizoku war
: human form is of a child
: attacking styles consists of snapping of fingers or moving hands as if conducting an orchestra; sometimes, the crushing of marbles which represents a living organism, once your marble is crushed, you're dead meat.

4. Deep Sea Dolphin
: Kai-ou (Ocean King)
: lives in the Demon Sea (if you look closely at their maps, it's in the west.)
: the sort of "rival" of Xelas Metallium
: lost the sanity (crazy in other words...as rumored.)

5. Greater Beast Xelas Metallium
: Juu-ou (Beast King)
: the youngest of the 5 Dark Leaders
: her base is on Wolf Pack Island, though it isn't written on the maps.
: Luna Inverse is her best friend
: her general-priest is Xelloss
: she can transform into a wolf anytime she feels like it.