Antichrist is destined to be an Antichrist?

There are various quotes in Sayings of the prophet about "Dijjal" the Antichrist. The tortures he put the believers through so that the Muslim God namely "Allah" could test the believers and the non-believers can be separated from the believers. So the question is: If nothing happens without the consent of Allah, **why the Antichrist is not destined for heaven as he is also obeying Allah** by strictly following the task (just a different sort of task) assigned to him and will be doing it well!