Board Thread:Lore Discussion/@comment-5262726-20140710051650/@comment-13446185-20140710130845

Morag Tong is also a Sithis worshiping group.

''"Sithis" is a corruption of "Psijii" which, in turn, was a derivation of the high concept PSJJJJ. Sithis was born when a nihilist sect of the already doom-ridden Chimeri merged (under Mephala’s tutelage) Daedric elements with the Inexpressible Action that was Padomay. In essence they began to revere Padomay's Chaos nature (as opposed to that of Anu, who is Order), and over the years degenerated into a thuggish mystery-cult which wanted to "murder the world." The Dark Brotherhood was born in these times-- which, in Morrowind, is known as the Morag Tong. Some of the higher-level Morag Tong maintain that they predate the Dark Brotherhood (more evidence of this later).''

-Source of Chaos