• The first volume of the manga released on October 20, 2012. Four years before the the anime premiered.
• Akihito Tsukushi previously worked for Konami on the following games: Elebits, The Sword of Etheria, Suikoden III, Loveplus, Dewy's Adventure.
• Nanachi was originally meant to die during the Idofront arc. Fans loved the character so much that the mangaka decided to keep her alive.
• Believe it or not Maaa has a canonical gender. The mangaka has stated that she is a female.
• The Abyss was discovered 1900 years ago.
• In the Abyss, time passes more quickly than on the surface.
• On April 1st, 2022, Akihito Tsukushi revealed that Nanachi was a male. This was, of course, an april fools joke.
• Reg's arms can extend up to 40 meters each.
• In the infamous ''papa pole'' scene from Dawn of the Deep Soul, the paper Riko uses to draw a penis is the same letter that contains Lyza's message.
• The same scene was also believed to have darker implications for the longest time. However, in one of the interviews, the author stated that the reason why Prushka calls it a ''papa pole/rod'' is because Bondrewd explained to her that it is the ''rod used to become a papa'' while dissecting animals.
• Kiyui is the only known survivor of the Birthday-Death disease.
• Irumyuui and Faputa share the same voice actor.