Abe no Seimei (安倍 晴明 Abe Seimei) is one of the main characters in The Story Begins. He is a human esotericist from Gi'on. He has an ambition to create life, in which he stumped. One day he finds out about Kouki and researched it. During one of his break at a local pub, he met a foreigner couple, Artair and Evangeline. Seimei listens to their story and offered to help with his wide arrange of knowledge. In battle, Seimei uses enchanted paper talismans and wields a ceremonial blade named Makai Tensei Tsurugi (魔界転生剣 Demon World Reincarnated Blade).

Seimei has black eyes and black hair in a ponytail. He is protective of his creations, but also firm in upholding established rules. He was almost always seen with his lavender keikogi, his red shinsen vest, and his white scarf. Artair once commented on how good Seimei's fabrics are.

Seimei's journey represents his belief system that helps others deal more comfortably with the unknown and the unpleasant. He needs support in the situation. In the end, however, he will have to face things by himself.

Seimei was named after a legendary onmyouji. His design was a homage to Tokisada of Shin Megami Tensei. He is 27 years old during the event of The Story Begins, 167 cm tall and weighs 65 kg.