Idora is one of the nine Ady Slate Horrors, and the Horror who possessed the body of an unnamed woman in white.
Idora was freed from the Ady Slate when a mysterious person destroyed the slate using a Madō Art technique. Idora was slain by Raiga at the harbor, but the seed of Eyrith she carried quickly transferred into one of her fellow Ady Slate Horrors before Mayuri could seal it. It is later discovered that Idora's essence survived because Mayuri's inner cage was left open, allowing her to persuade Mayuri into eating humans and becoming a Horror herself. Raiga eventually uses a Makai spell to enter Mayuri's consciousness and saves Mayuri by defeating Idora.
- Idora was the 5th of the Ady Slate Horrors to be captured, and it was the first Ady Slate Horror to be the holder of Eyrith's seed.
- http://garo-project.jp/TV4/horror/?file=14 -Idora's Official Profile