The locations of the Berserk Legendary Boss were distributed in different maps. These included the Fallen Cemetery, Title Shrine, Thunder Flame Cave, Heavenly Domain, Death Shrine, Root of Evil, and other maps. These Bosses would respawn every six hours, but they could not be used as the main way to obtain Essence Soul Stones. Compared to staring at these Bosses, players could obtain Essence Soul Stones faster through various activities.
I don't have the exact name of the person who created the Omori manga at hand. It could be worth doing a search on manga databases or asking fellow manga enthusiasts for the answer.
Omori is purely fictional. The story and characters were imagined by the creators, not drawn from real-life events. It offers a fantastical and imaginative experience for players.
At the moment, there's no definite date for the Omori manga release. But you can follow the official social media accounts or manga forums for any potential news or leaks.