User blog comment:Jopjopjop/Volume 20 Spoilers/@comment-104.7.80.176-20150721190514/@comment-104.7.80.176-20150721215557

Also sairaorg is the only pureblood devil they respect as he became powerful without any special demonic powers and because he was able to hold his own against their brother who also respects him. Plus his defeat at issei's hands proved to everyone just how strong their baby brother really is and their grateful to him for that.