The Evil Seed was an event depicted in Soulcalibur Legends and the Soulcalibur opening sequence, where a bright beam of light shot into the sky from Soul Edge after it accepted Siegfried as its rightful owner. According to New Legends of Project Soul this was because Soul Edge had become unbalanced and enraged by the death of Cervantes and the destruction of its other half.
- A French noble went mad and attacked fellow nobleman Raphael Sorel, only to be killed as Raphael defended himself.
- Aeon Calcos, then still human, went mad and slaughtered an entire village of people.
- Gel-o-Fury, a demon, broke free of his imprisonment in the Bamboo Shrine of Ōmi Province.
- The Grand Labyrinth where Olcadan was imprisoned was opened.
- Hilde's father, the king of Wolfkrone, went insane.
- Monks of the Ling Sheng-Su temple went mad and started killing each other. Kilik was the only survivor, thanks to the sacrifice of his adopted sister Xianglian.
- Talim fell into a coma for a number of days.
- The literal translation of 'Evil Seed' from the original Japanese term is 'Evil Sperm'.