What are the routes of Satanism?

I know that it is a particularly shunned religion, but I am semi curious about it, because of the fact that I know so little about it.. What do satanists believe in, and where does the religion originate?

You might get better (and more informed) answers if you post in religion. You've posted in words and wordplay.

The concept of an evil force derives from Zoroastrianism. This was the "improved" religion the Persians took along on the efforts of Cyrus the Great to concur the known world. When Cyrus defeated Babylon he considered the indentured Hebrews to be non threatening since they were enslaved (yet again) by Babylon. The Hebrews were set free and allowed to remain. They were exposed to educated Persians (educated by Greek Scholars) and took the opportunity to make one of the major revisions to Judaism namely, they stopped blaming bad things on VHWH and began blaming them on this evil force invented by Zoroaster.

When the ?new Jews?, later to be called ?Christians?, began to write their bible (4Th century) they borrowed the idea of an evil force and named it the ?devil?! The stole the Greek god of the underworld (Hades) and used that name for the devil?s real estate, ?hell?!
(Note: I tend not to capitalize made-up religious names.)

So, really, devil worship is made possible by Christians! Credit where credit?s due! The irony should be obvious.

You can learn so much more about it at JoyofSatan.com
Go there and it will fill you in with all the details.