I heard Messenger of Allah (way peace be upon him) as saying: The throne of Iblis is upon the ocean and he sends detachments (to different parts) inorder to put people to trial and the most important figure in his eyes is one who is most notorious in sowing the seed of dissension.
سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ إِنَّ عَرْشَ إِبْلِيسَ عَلَى الْبَحْرِ فَيَبْعَثُ سَرَايَاهُ فَيَفْتِنُونَ النَّاسَ فَأَعْظَمُهُمْ عِنْدَهُ أَعْظَمُهُمْ فِتْنَةً