This article or section contains untagged major spoilers for all of Umineko no Naku Koro ni, possibly including the manga. Readers who have not completed the story are advised not to proceed further.
Ikuko Hachijo (八城 幾子 Hachijo Ikuko) is a mystery novelist who is responsible for taking in Battler Ushiromiya after the Rokkenjima Mass Murders and giving him the new name of Tohya Hachijo. The two of them fabricated stories about the Rokkenjima Mass Murders under a shared pseudonym.
Ikuko appears as a young woman with mid-back purple hair. She wears what appears to be a brown strapless dress with several ruffles and a yellow ribbon in the front with a green colored gem near the bottom. Over this she wears a light colored jacket that reaches to her knees.
Ikuko is an eccentric and anti-social individual, having no friends or companions besides her black cat Bern. Ikuko claims that writing novels used to be fun when asked by Tohya about her pastime, however she seems to enjoy writing novels together with him.
According to Tohya, Ikuko was the daughter of a very well-off family and was almost disowned due to "various mischievous incidents". Ikuko was sent to live in a mansion by herself, where she lived peacefully with hired servants and spent her time reading and writing detective novels, her manuscripts going unseen by anyone else. One rainy day in 1986, Ikuko chanced upon a nearly-drowned Battler on a road, who escaped Rokkenjima after the mass murders but developed brain damage and amnesia.
Ikuko took Battler to live with her and gave him the temporary name of Tohya. She offered to give Tohya brain surgery to lessen the pain of his frequent headaches, but he declined out of concern for harming his past self. One day, Tohya began reading some of Ikuko's manuscripts and convinced her to start publishing them. The duo put together their best ideas and wrote The Strange Tale of Kurokubi Island, considering it to be a masterpiece. The night after, Tohya woke up to see Ikuko reading on her computer about the Rokkenjima Mass Murders, the woman taking interest in the rumors and forgeries surrounding it. Tohya began to recover his memories of Battler and struggled to control himself. Tohya and Ikuko would then begin writing their own Forgeries to try and help Tohya retrieve his old memories.
In the Twilight of the Golden Witch manga, Ikuko discovers a message bottled titled "Confession of the Golden Witch". It contained the confession of Yasu, the writer of the original two message bottles.
- Ange Ushiromiya (acquaintance)
- Tohya Hachijo (shared pseudonym, friend, colleague)
- Tohya Hachijo (pen name) (representation of Tohya and Ikuko)
Ikuko has been presented prior to Twilight under the pseudonym Tohya Hachijo.
The nature of Tohya Hachijo being two people is revealed in this arc.
In the ???, decades after Ange has established herself as the author Yukari Kotobuki, Ikuko and Tohya meet her and reveal the truth about Battler's fate. They attend a Halloween party at the Fukuin House where Battler's memories are put to rest.
- Ikuko and Tohya Hachijo are the only characters with sprites who are never included on the character screen.
- According to Umineko Episode 8 Shinsou Kaimei Dokuhon:
- 07th Expansion All Character Settings Collection
- Episode 8 Shinsou Kaimei Dokuhon page 17: "She often says things that make her seem like Ryukishi07's proxy, but that's definitely not the implication. In fact, I've characterized her based on ○○ sensei. If it weren't for ○○ sensei's valuable advice, I'm sure I wouldn't have been able to write all the way up to EP8. ○○ sensei, you have my deepest gratitude."