Three days before Armageddon, a drug addicted lawyer struggles to be free from his addiction, his friends and his day job .The devil has marked him, he has made a claim .To survive the Dreadful war he has to beat him at this final hour.

Agreed with the above comments.

Also the premise is confusing - how does he know that Armageddon is three days away? Is he the only one that knows or do all people know?? Why not just set it during Armageddon instead?

Lastly best to describe exactly how one beats the devil himself, this sounds implausible according to mainstream theology. Perhaps best if he needs to banish the devil not beat him.

Yes, clumsy. ?And confusing. ?The character has 3 ?objective goals: ?kick drugs; dump his friends; ?quit his job. ?Well, which one is it?

(And why must he dump his friends and/or quit his drug to save his soul?)

CraigDGriffiths nailed it nicely I think.