Since Satanists worships the Christian Devil, would that be a Christian denomination or a religion in and of itself?
Now, Jesus says this:
Then John said in reply, “Master, we saw someone casting out demons in your name and we tried to prevent him because he does not follow in our company.” Jesus said to him, “Do not prevent him, for whoever is not against you is for you.”
Luke 9:49-50 - NABRE
and it doesn't take a rocket scholar to complete the syllogism that whoever is against you is not for you.
Now, this is a sort of good question because other "semi-Christian influenced groups" Islam, Manicheanism, Catharism, maybe Buddhism, Scientology and other clearly Christian groups Jehovah's Witnesses, Mormons and Christian Scientists, have varying overlaps Buddhists being probably about 20% and Mormons 90%.
I know nothing about Satanism, and I don't want to, I would think that an evil god would be possible to conjure up without any Christian influence, there are plenty in the Old Testament. What isn't possible without Christian influence is a black mass or some such blasphemy, so in that sense, yes they tie themselves to an opposition of the True Faith and commit their atrocities in that light.
Is Satanism a denomination of Christianity?
There is no denomination within Christianity that upholds the belief that Satanism is a Christian denomination.
There are many and very divergent beliefs within Christianity, but this is not one of them.
Christians do not reverence Satan, Lucifer or any other demons whatsoever.
Luciferianism is a belief structure that venerates the fundamental traits that are attributed to Lucifer. The custom, inspired by the teachings of Gnosticism, usually reveres Lucifer not as the devil, but as a savior, a guardian or instructing spirit or even the true god as opposed to Jehovah.
In Anton LaVey's The Satanic Bible, Lucifer is one of the four crown princes of hell, particularly that of the East, the 'lord of the air', and is called the bringer of light, the morning star, intellectualism, and enlightenment. The title 'lord of the air' is based upon Ephesians 2:2, which uses the phrase 'prince of the power of the air' to refer to the pagan god Zeus, but that phrase later became conflated with Satan.
Author Michael W. Ford has written on Lucifer as a "mask" of the adversary, a motivator and illuminating force of the mind and subconscious.
Furthermore practicing the occult and witchcraft are forbidden in almost all denominations.
The Cathars held that Lucifer (Satan) and Jesus were brothers!
In the Bogomilband Cathar text Gospel of the secret supper, Lucifer is a glorified angel and the older brother of Jesus, but fell from heaven to establish his own kingdom and became the Demiurge. Therefore, he created the material world and trapped souls from heaven inside matter. Jesus descended to earth to free the captured souls. In contrast to mainstream Christianity, the cross was denounced as a symbol of Lucifer and his instrument in an attempt to kill Jesus.
The answer is no on a couple of accounts.
- First off, strictly speaking, Satan, or the devil is not an exclusively Christian belief, so referring to a "Christian devil" is a bit of a misnomer, although perhaps understandable in one sense since satanism has been mainly opposed by Christian groups.
- Satanism is a broad term that covers various belief systems, some of which do not believe in a satanic persona per se, to those that actively worship Satan as a deity (https://en.m.wikipedia.org/wiki/Satanism).
However regardless of their actual stance, most espouse views that are in direct opposition to the Christian faith. (I only say most, as I recall reading a long time ago about some supposed satanic groups that claimed to be almost saintly in their belief systems, but could not find any similar report today). Either way, no satanic group can be considered a Christian denomination.