User blog comment:B214/DxD Zero: Sirzechs story/@comment-162.252.126.39-20181027201031/@comment-37165251-20181027203215

The One-Sided fight came mostly because of Ajuka´s Technique "Kankara Formula" which can take control of his enemies' demonic power attacks, change their shape, direction, and also increase their power.

This is because of his interrest in Calculations which lead to his development of this Technique. It seems only Sirzech Lucifer is able to overcome it (maybe because his Powerlevel is the same or because his will is strong enough to cancel the Influence of Ajukas Kankara Formula).

Personaly I think the Clan Power of the Astaroth has to do with Barriers (we saw Ajuka and Diodora creating very strong Barriers with ease)