The Devil Confesses: My plan was to fool people into following Religion.
The Devil. being smarter than humans, convinced them to follow a book blindly without question and put their undying trust into a simple fallen man and then called it faith.
Most people think that the Devil is the villain of the bible when it is obvious who the real villain is, the same entity who slaughtered all of the animals and people and made an impossible book to follow - Yahweh. But what a better trick to send people to Hell than to convince people that if they followed the way of God, then they will be saved.
"They have been justifying atrocities that any sane person would see as horrendous." said Satan. "It's quite remarkable that humans are so malleable."
In a carefully set up plan, Satan has been manipulating people to think that everything they read in the bible is 'God's will', like slaughtering children for making fun of a bald guy. "I thought I was caught with that one, but here we are. Religious people follow the bible like they would melt if they didn't."
"I learned early on that people don't want to be accountable for anything, but have something that they can justify their evil on. Bam! I created religion. Well, most religions. What's up with the Jains?"
It was hard keeping track of everything. It turns out that he kept several notebooks, but kept losing them and finding them again. "Yeah, that's how we got the gospels." But in reality, I would just do horrible horrible shit and blame it on God and in the end it was alright. I left the faucet on and drowned the earth, and everyone, EVERYONE died except some 950 year old dude. I blamed it on God. It turned out fine."
Satan can't believe people can't see past this charade. "Christians are hateful and spiteful people who will turn on you at the drop of a hat. Muslims will kill you for drawing pictures of Mohammed. Come on people."
JESUS ON THE CROSS
Satan admits that he did pull a bad by sacrificing some dude on the cross. "He was some nobody who thought he was the be all and end all." explains Satan, "I even messed with him in the desert so he would think he was the guy." In the end, it was a small price to pay to put his plan into action. Look at where they are now.
When asked why he revealed his intentions now, Satan sat back in his chair and said this, "It's not like they'll believe you. I can shoot a guy in the middle of fifth avenue and nothing would happen to me."