TV-Series
Description
Souichi Tsujii is an 11-year-old boy living with the Tsujii family. He insists he was born on June 6 at exactly 6:06:06, though his true birthdate is May 3. Afflicted by anemia, he habitually chews steel nails to counter his body's iron deficiency; he sometimes shapes these nails into fangs and declares he needs to consume blood because of his condition. This anemia also gives him a pale, thin look.

Eccentric and isolated, he mutters to himself and laughs alone, behavior others find disturbing. Unpopular and a loner at school, he misreads attention—like whispers or glances—as admiration. Raised mainly by his grandmother, he shares a strong physical resemblance to her. He holds resentment towards his older brother Koichi and cousin Michina, frequently targeting them with pranks or curses. A rivalry with Michina stems from their shared birthday.

Souichi practices Onmyōdō and black magic, using Katashiro dolls to cast curses. Harming these dolls—nailing, burying, or submerging them—causes corresponding effects on the person they represent, from hallucinations to injuries or hospitalization. He manipulates weather through curses and claims he can communicate with any doll. His abilities extend to generating nails from his mouth and projecting them like projectiles. He builds complex spaces, like a four-layered soundproof room, and mimics natural sounds like cicadas to unnerve others. These powers show no apparent range limits, with curses affecting people as far as Tokyo.

His actions often backfire comedically. Trying to scare his sister Sayuri with a spider fails when his brother returns it, exposing Souichi's own fear. Adopting a toad to frighten her, he accidentally kills it through improper care. In "Fun Summer Vacation," his doll curse results in his cousin Yuusuke nearly drowning. Michina later slaps him during a vampire-themed threat, driving his nail-fangs into his cheek. During "Fun Winter Vacation," he traps visitor Yumiko Fukaya in a pit, falsely claiming to drink her blood; he later suffers a stomachache after consuming snow mixed with strawberry syrup.

Family lore involves a twin brother named Souji, said to have died in the womb. His grandmother insisted Souji existed and interacted with both boys. During "Souichi's Birthday," the spectral forms of his grandmother and Souji manifest to menace Michina. Souichi stops the haunting upon discovering Michina saved his nail-embedded cake slice.

As an adult, he masters advanced dark magic, producing nails directly from his mouth. He binds family members into grotesque forms, forcing them to run his haunted house business. He marries Miss Fuchi, and they have a cannibalistic son resembling her. Fleeing his family, he adopts a nomadic life, setting up haunted houses in various towns. His wife eventually finds him, threatening death if he abandons them again.

Souichi occasionally shows unintended benevolence. In "Souichi's Convenient Curse," he misreads a classmate's romantic awkwardness and tries to help via curses, though his main goal is still to frighten. His work on Koichi's soundproof room includes hidden passages for pranks, yet a carpenter's praise for his nailing skills briefly lifts his confidence.