In the world of DXD, many species reside which vary in powers and beliefs. these species have been divided into factions and one of the most prominent factions is the biblical faction which is mainly a faction of 3 species angels, fallen angels, and devils.
During the great war, the leader of the angel's biblical god, and the leader of the hell faction the devil/Satan work together to seal the biggest calamity their dimension has faced the Trihexa, and after both engaged to the battle to the death in which the leader of the hell faction came on top which led to the end of the hell faction became the winner of the war but after the battle between biblical god and Satan.
Satan was attacked by his brethren Lucifer, leviathan, and Beelzebub in order to take control of hell from him but even in his weakened state Satan was able to kill all 3 but at the cost of his life which led to leadership falling into the hands of their descendant, due to the heavy loss and the death of strongest individuals in their faction all 3 species came to an agreement to not reveal the truth about the death of the god and call a piece time period between them.
In memory of the first devil king, Satan the name of the hell faction was changed to devil faction. During this time of peace, all species live in relative harmony and started working to grow in power.
During this time the 3 first devil family started getting arrogant and forcing rule on their people more harshly and they even try to get the support of the strongest house of all devils the Satan house but they remain neutral not wanting to be part of any side. After a few centuries of tyrant rule a civil war started in the devil faction which led to all 72 pillars being torn apart after years of war Satan's house was also forced to participate to save the underworld from destruction during this time lord of Satan's house Minato Satan was approached by 4 teenagers to train them so they help their war and after years of training those 4 became the factor to change the war with the original families and after their victory, they came as the winner and were able to repel original leaders and were then given the title as 4 Mous they were Sirchez lucifer, Ajuka Beelzebub, Serafall leviathan and Falbium. After becoming the leader.
The 4 Mous give their teacher the unofficial title of devil king because of being the current strongest devil and the teacher to 4 Mous.
After many years passed with new systems like peerages and rating games being introduced it came a time when the new generation started carrying the burdens of old in this time in the household of Minato Satan was waiting for his wife and servant to come with the news of his son he was with all the 4 Satan and some close friends like lord and lady phoenix and Gremory, Grayfia Lucifuge, lord and lady Sitri.
After a few minutes, the crying of the child resounded in the hallway after which everyone ran towards the hall to find the mother of the child sleeping and a yellow hair kid sleeping next to her with a peaceful expression. when they came and started celebrating and also when they up close they also thought why he has 6 whisker-like marks on his cheeks. after which the mother named him Naruto Satan the prince of devils.
As they can also sense his devil power from him which was rather high for a newborn child. after a few hours of celebrating and discussion, it was decided that the news of Naruto being his will be kept a secret till his mother is able to get her powers that she lost to being weakened in childbirth back. which would take around 7 to 8 yrs.
To save him from some old-thinking families who wanted revenge and what would be better than killing the only last Descendant of Satan.