Omegavers. In this world, the secondary sex can be recognized immediately if there is a birthmark. Most often, the mark is very small, like a birthmark and is located behind the ear, on the collarbone, pelvis, fingers or toes, sometimes even the neck.

When Dazai appeared at the agency, everyone saw the mark on his hand in the Alpha symbol, and he was tall, so there were no questions for 4 years.

On one of the missions, Dazai severely injured his head and fell into a trap with Kunikida. Kunikida was bandaging dazai's head with bandages to stop the bleeding and noticed a real mark behind his ear, the mark of Omega.

Kunikida was surprised, but said nothing. -How are you feeling now? Kunikida asked