First you need to understand what the common interpretation of "Satan" is, because beginners often mix them up.
This message will be prefixed with the words: "I believe the following to be a probable theory of truth", and it is the individual's duty to research the matter using the theories as a tool to further understand the truth.
Christian/Anti-Satan establishments have often depicted Satan to be an external entity of high power, tricking Eve and Adam to eat an apple or tempt prophets in the dessert. By that definition, Buddha also fought it and called it Maya, tempted by lust and illusions. Because of the idea that it's spirit exists externally, astrally or hidden in physical, the atheists have created a belief that it is nonsense for Satan and spirits to exist and thus neglect the existence.
"The greatest con he ever pulled, was making the world believe he does not exist."
"The greatest con he ever pulled, was making you believe he is you."
"The simpler and older the con, the easier it is to get away with. Firstly, because the victim thinks: It can't be that simple, and: it can't be that old. That is why it works."
"The enemy will hide in the last place you will ever look."
"You will find the enemy in the place you do not wish to go." (Fear)
The big spoiler alert is simple: The voice in your head you take for granted to be you, is the Christian tempter of the serpent. Because Satan is inherently a completely different deity, they just call all heresy and sodomy, the spawn of the devil. So it's a scapegoat scenario.
Once you get your thoughts in control and can practice mental silence for hours, you can connect with the universe/all just like Job, Jesus, Moses, Buddha and more. It takes many months and hours per day to achieve this state of presence, and thus ego often convinces the soul to abandon the quest for a more achievable pleasure.
The voice in your head tells you what to think, what to feel, when to masturbate and what to eat. It channels through your body, lies, slander and boasting with pride as to make you seem bigger than you are. When you become conscious, you will have no need to pretend anymore, because you will know who you are.
When you're in control of the mind, you can also choose what it is you wish to do, as opposed to let the mind voice decide for you and then walk around being angry during the days. In the silence of the mind, your heart speaks to you and you can feel it. No words, no thoughts, only presence.
Good luck.