User blog comment:B214/Question and Answers 6/@comment-39829421-20200103092954/@comment-5384276-20200103103256

It changed during the events of DxD. The Five Principal Clans serve the Shinto gods and revere them. Due to the clans service to the Shinto Gods, the gods grant them a variety of supernatural abilities which is eastern version of magic for instance the Himejime's ability to control fire.

The Youkai and Five Principal Clans used to be opposed to each other when they were being lead by the former heads such as Suou Himejima who were very old fashioned and refused to be flexible.

But under the new heads such as Suzaku Himejima and after the Three Great Powers formed an alliance and due to the actions of DxD, the Youkai & Five Principal Clans began to cooperate with each other to protect Kyoto.