Io is a mysterious individual encountered in the Serdin Kingdom. She claims to be a detective in search of the culprit that is responsible for what she calls an "erosion of souls" among living beings in Bermesiah.
A person of unknown origin, Io seems to possess immense strength as shown when casting a purification spell upon those who were affected by the contamination all at once and is capable of borrowing Rin's divine powers. She also managed to eliminate the pain that was tormenting Edel's right eye for years.
In her conversations with Rin, Asin, and Edel, Io keeps referring to them as "humans" suggesting that she isn't a human herself.
There is nothing else known about Io other than that she seems to be working for someone whose identity is yet to be revealed.
As a boss
Io can be fought as a boss in Act 23.6: ???.
- Io noticeably has developed a fondness for Edel throughout their journey in Bermesiah.
- Main article: Grand Chase Dimensional Chaser/Gallery