Corrupted monsters are a special class of mythic monsters. Corrupted monsters can only be ranked up using their own cells, lutum, or Nectar They also have the ability to perform a cap breakout, allowing them to rank up to intermediate steps with less Lutum. Additionally, players may have only one copy of each Corrupted monster.
The Corrupted Era Saga followed the story of a mysterious Lord - who turned out to be the return of Lord Nebotus - who, using Lutum, corrupted Fayemelina into Fayemalice, strengthening her and turning her to unadulterated evil. He gave her a corrupting root and instructed her to corrupt more monsters to serve in his army.However, Fayemalice found that using the corrupting root on purehearted monsters instead Purified them, making them stronger, but not turning them evil. Sensei Pandaken and other members of the Honor Dojo defeated Fayemalice and took her original corrupting root to use to grow their own ranks, and a conflict ensued between the new Purified monsters and the Corrupted forces of Lord Nebotus.
Ultimately, Lord Nebotus was defeated by Pure Pandalf and banished into the black hole left behind by the severed Cosmic Portal.