Lord of the Mysteries: Klein's Classmate

On the night of the crimson moon, at the moment Klein was born, another spirit descended at the same time.

Eric Abraham, the true form of the Master Key, had his memories from Above the Gray Fog unsealed amid the interweaving of authorities when he was sent into this world. He vaguely recalled the fall of civilizations and the battles among the Pillars. The Gray Fog's passive protection and his own resistance kept him from being corrupted. These memories also made him realize that he could no longer return to his homeland.

He glimpsed the Sefirah Castle, but had no chance to enter. He knew that another fellow Earthling was stranded in the world, but had not the slightest clue where to find them.

In an age when the gods maneuvered against one another, the extraordinary journey of a stranger began.

Far away in Tingen, a legend had just awakened.

(Klein and the protagonist are co-leads. The protagonist won't take the Sefirah Castle. I'll do my best to stay true to the original. I've reread Lord of the Mysteries five times, but have only read Circle of Inevitability once. Suggestions are welcome, and I'll be sure to read them.)