The Devil has since ancient history been the adversary of God, the opposite of God.
The Devil has many faces and is always waiting to make new victims.
In a psychological sense, every human has his/her positive sides, and his/her negative sides. Only by being aware of your negative sides can you overcome them.
The number this card carries is 15, composed that is 6. The resemblances to the first '6' card (The Lovers) are remarkable; in both cards security is a central theme.
With The Lovers, you made the choice against old securities yourself, with The Devil you will lose them due to outside influences.
The Devil is a very important card in the cycle. An enormous amount of work has to be performed at The Devil. Facing your fears will be a large part of that work.
The Devil kind of forces you to face your future.
Don't avoid change. Seek some security outside yourself, away from your inner troubles.
The Devil announces a bad time in your life, which also allows you to experience new heights later. After this bottom at The Devil you can only go up. You're busy changing, and in that process you now encounter your own fears. And you might not even recognize this!
This is not the time to face your own fears. Other issues in your life had better take priority.