User blog comment:B214/Volume 23 discussion blog/@comment-78.49.82.128-20170426022646/@comment-30924344-20170426121449

Ajuka, Sirzechs, and Azazel decided to make Issei the leader of ExE in the future which is more important than the 7 Satans so they obviously believe Issei has great decision making/leadership skill potential. He's gaining experience from this tournament which is good.

Anyways maybe not who will replace Lucifer, Leviathan, and Asmodeus, but the 3 people who become the new satans. Two people we know who become two of the 3 new satans are Roygun and Diehauser. Roygun is close to Issei and will understand her good intent she had and would choose her to become a Satan to redeem herself for the Underworld. He would choose Diehauser to help make sure what he fought against utterly does not happen at all and to redeem his crim of helping Rizevim. The third new satan is somebody from the Amon clan [most likely the heir/heiress] and Issei knows the second son who is Iolava. The heir/heiress will most likely introduce themselves in this tournament though not in a match, and they will apologise to Issei for Iolava's attitude. If Issei is trusted to lead an organisation then he can be trusted to choose three new people to lead the Underworld. Ajuka himself would feel Issei is the best choice because as Issei is a hero to the Underworld, him deciding to choose Diehauser, Roygun and that Amon member will get more support than him doing it.