Imperial Seven

The Imperial Seven(, lit. seven sinful warlords) is the title idealized by the current Seven Demon Lords and given to Seven Young devils who for a reason or another possesses an abnormal trait and/or ability which places them above their peers and as strong candidates to become Demon Lords in Highschool DxD: Яe-birth.

Each young devil also possesses a crest(, lit. sin) under them, and are considered destined to either bring the rise or downfall of the current devil society and order in the future.

Summary
The title was first mentioned during the Devil gathering in Volume 11 of Highschool DxD: Яe-birth by Odin and Chaos, and later explained by Calico Belphegor. The Imperial Seven refers to Seven Young Devils from the 72 Pillairs who are considered both the Underworld's trump cards as well their biggest threat due to a specific trait in them as well as an innate abnormal level of power which cannot be reached by any other devil of same age no matter how much they train. According to Calico, only one Imperial Seven can defeat another at their peak.

Because they are considered abnormalities, they are under constant survaillance and their natural talent and development, encouraged by others. They are also given a label according to their trait and power, called a Crest, which gives an idea about their personality and power, while as well as their weaknesses.

Young devils, in order to avoid Ostracism for the Imperial Seven, are not informed about such.

Trivia

 * The idea of the imperial seven is vaguely based on the Seven Deadly Sins manga. They are also somewhat based on the Royal Knights from Digimon.
 * Of all the Seven, Berolina is the only one so far to have dragon-based evil pieces.
 * Midaller is also the only member who is also under someone else's peerage.