User blog comment:Collbrande-Ex-Caliburn/Hyoudou Issei's Peerage composition hopes/dreams/hypothesis/@comment-10330822-20161112235347/@comment-10330822-20161122052336

Well, if I recall correctly. Devils have a hard time breeding, while Angels can't replish their numbers easily without God. Hence why the Evil Pieces and Brave Saints are so important to the futures of the Underworld and Heaven. However, the Gigori are never stated to have problems breeding. In fact, their numbers rose after the events of Volume 18 after the traitors to Heaven became Fallen Angels. So, the Gigori already have two ways of multiplying; normal breeding, which seems unrestricted, and the falling of normal Angels. So, it makes sense that Azazel doesn't need EP or BS for his faction, they can recover without tips or tricks.

Azazael was studying Ajuka's EPs to modify the system for the BSs, and open the door for them to be freely traded between the two, which would revolutionize the Rating Games. It was part of the reason Michael agreed to the three way peace treaty, because Azazel and Ajuka could provide invaluable research and development to increase Heavens forces. The Brave Saint research system was in the 5th Heaven, which was destroyed by Trihexa. So, without Michael and Azazel, its questionable whether this research can continue, even if Gabriel is holding the reigns of Heaven.