20,000 plus years ago, Sinister was a very minor godling of chaos, mischief and yes, he stole left socks.He was the laughingstock, whipping boy of the evil pantheon he belonged to. Cursed(gifted?) with incredible durability so the other gods could beat, burn and torture him. In his very slim spare time he stole the left socks of children while they slept.
Things changed with the coming of the Star Whales and the every thousand year apocalypse they brought. During the end of the 4th cycle, the remaining non-evil gods convinced Sinister's pantheon to make an ultimately futile last stand against the onslaught. All of the gods, demi-gods godlings and their followers were destroyed. Starting the current cycles of death and barbarism.
He was the only survivor,his pantheon wouldn't let him 'play"
He laughed for 37 years.
During the remaining years of the 5th cycle, Sinister went about his merry way. Stealing left socks, spooking dogs and other minor mischief. He had no interest in attracting the attention of any gods who might be in hiding.
By the 7th cycle, he was convinced that alone of all the gods, he remained. At first this lead to bolder and bolder pranks, by the end of 7 he was taking left feet. During 8 he started to torture and murder to his hearts content, Fulfilling the evil fantasies of a totally warped mind to the utmost.Then he ran into his first group of adventurers. It did not go well for him. The powerful group nearly succeeded in killing him. He barely got a way with a far too clever illusion. a few hundred years later the same thing happened again. He spent the last 25 years of the cycle thinking of a new way to cause the chaos he felt he deserved.
It finally came to him. He could do bad thing through followers. And he perfected his art over the next few cycles.
Sinister goes into a medium to large city and sets up three different evil cults. After about 10 years he pits them against each other in a competition of blood, carefully causing the deaths of any up and coming adventurers. He does this until the city burns. By going to widely different regions on different continents he is never found out. Also having a stable of about 30 different cults to pick from, continues his disguise.
In reality, he looks like a grotesque red and black dwarf clown. When he manifests to followers he takes on a fearsome visage, usually one of the gods who came before. He is only moderately powerful as a higher than normal adventurer with a specialty in illusion. He is as durable as the largest of dragons.
THE CURRENT CULTS
The Followers of BOK-very similar to the Thugee cult. Sinister appears to them as a Black alacorn
The Book and The Wrack-an intellectual cult that is given power for torture. He appears to them as Thorvin, Master of Dark Tomes( a wicked librarian)
The Order of Mendurak the Thirsty-Blood collection and baths a specialty, appearing as a Blood Elemental
Sinister is the only being with the knowledge of the cycles, and that suits him just fine. If you could catch him and get the information out of him, it would be a tremendous leg up in a otherwise fruitless battle with the Star Whales
The adventurers are seen as getting too powerful, one of the cults step in.
Stop the ultimate destruction of the city.